DigitalOcean App Platform: yarn build errors should halt/fail deployment; currently does not

[Ambient-Impact]

After trying various things (see comments), this is starting to look like more of an issue with App Platform because the implemented fixes (again, see comments) seem to correctly exit if yarn build:deploy fails when run under DDEV.

See also follow ups #56 and #57.

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Here's an example Sass compile error that failed but didn't cause the deployment to fail, leading to missing styles and other assets:

2024-02-09T15:52:09.140850293Z �[34m│�[0m ➤ YN0000: Done with warnings in 2m 1s
2024-02-09T15:52:11.656251505Z �[34m│�[0m [ Run Order ]-------------------------------------------------------------------
2024-02-09T15:52:11.656579322Z �[34m│�[0m └─[0] web/modules/custom/ambientimpact_core
2024-02-09T15:52:11.656595094Z �[34m│�[0m   ├─[1] web/modules/custom/ambientimpact_icon
2024-02-09T15:52:11.656599221Z �[34m│�[0m   ├─[1] web/modules/custom/ambientimpact_ux
2024-02-09T15:52:11.656602525Z �[34m│�[0m   ├─[1] web/modules/custom/omnipedia_block
2024-02-09T15:52:11.656605799Z �[34m│�[0m   └─[1] web/modules/custom/omnipedia_changes
2024-02-09T15:52:11.656610063Z �[34m│�[0m     ├─[2] web/modules/custom/ambientimpact_media
2024-02-09T15:52:11.656613435Z �[34m│�[0m     └─[2] web/modules/custom/omnipedia_content
2024-02-09T15:52:11.656617021Z �[34m│�[0m       └─[3] web/modules/custom/omnipedia_media
2024-02-09T15:52:11.656620331Z �[34m│�[0m         └─[4] web/themes/custom/omnipedia_site_theme
2024-02-09T15:52:11.656624252Z �[34m│�[0m 
2024-02-09T15:52:11.656628058Z �[34m│�[0m [ Run / Command: build / Concurrency: 6 ]---------------------------------------
2024-02-09T15:52:17.014273677Z �[34m│�[0m ✅ web/modules/custom/ambientimpact_core                                   5.28s
2024-02-09T15:52:25.326065378Z �[34m│�[0m ✅ web/modules/custom/omnipedia_changes                                    8.22s
2024-02-09T15:52:26.888978325Z �[34m│�[0m ✅ web/modules/custom/omnipedia_block                                      9.75s
2024-02-09T15:52:27.433859052Z �[34m│�[0m ✅ web/modules/custom/ambientimpact_icon                                  10.32s
2024-02-09T15:52:29.873722176Z �[34m│�[0m ✅ web/modules/custom/ambientimpact_ux                                    12.73s
2024-02-09T15:52:37.094099100Z �[34m│�[0m ✅ web/modules/custom/ambientimpact_media                                  9.60s
2024-02-09T15:52:38.153614890Z �[34m│�[0m ✅ web/modules/custom/omnipedia_content                                    8.21s
2024-02-09T15:52:42.849986360Z �[34m│�[0m ✅ web/modules/custom/omnipedia_media                                      5.66s
2024-02-09T15:53:00.619034988Z �[34m│�[0m ❌ web/themes/custom/omnipedia_site_theme                  (exit code: 1) 17.67s
2024-02-09T15:53:00.622275459Z �[34m│�[0m 
2024-02-09T15:53:00.622302233Z �[34m│�[0m [ build for All ]---------------------------------------------------------------
2024-02-09T15:53:00.622307145Z �[34m│�[0m 
2024-02-09T15:53:00.622310716Z �[34m│�[0m --[ Output: web/themes/custom/omnipedia_site_theme ]----------------------------
2024-02-09T15:53:00.622314634Z �[34m│�[0m  ERROR  Failed to compile with 2 errors3:53:00 PM
2024-02-09T15:53:00.622318799Z �[34m│�[0m  error  in ./stylesheets/components/tooltip.scss3:53:00 PM
2024-02-09T15:53:00.622337087Z �[34m│�[0m Module build failed (from ../../../../.yarn/__virtual__/sass-loader-virtual-4cc529dfd6/0/cache/sass-loader-npm-13.3.3-f5ea4bd230-32bdb99afc.zip/node_modules/sass-loader/dist/cjs.js):
2024-02-09T15:53:00.622341181Z �[34m│�[0m expected ";".
2024-02-09T15:53:00.622344578Z �[34m│�[0m     ╷
2024-02-09T15:53:00.622347719Z �[34m│�[0m 245 │           width:  var(--tooltip-exaggerated-shadow-size);
2024-02-09T15:53:00.622351413Z �[34m│�[0m     │                ^
2024-02-09T15:53:00.622354613Z �[34m│�[0m     ╵
2024-02-09T15:53:00.622358793Z �[34m│�[0m   stylesheets/components/tooltip.scss 245:16  root stylesheet
2024-02-09T15:53:00.622362152Z �[34m│�[0m  error  in ./stylesheets/components/tooltip.scss3:53:00 PM
2024-02-09T15:53:00.622365753Z �[34m│�[0m Module build failed (from ../../../../.yarn/__virtual__/mini-css-extract-plugin-virtual-55e053d32b/0/cache/mini-css-extract-plugin-npm-2.8.0-f84e80660f-c1edc3ee0e.zip/node_modules/mini-css-extract-plugin/dist/loader.js):
2024-02-09T15:53:00.622369636Z �[34m│�[0m HookWebpackError: Module build failed (from ../../../../.yarn/__virtual__/sass-loader-virtual-4cc529dfd6/0/cache/sass-loader-npm-13.3.3-f5ea4bd230-32bdb99afc.zip/node_modules/sass-loader/dist/cjs.js):
2024-02-09T15:53:00.622372742Z �[34m│�[0m expected ";".
2024-02-09T15:53:00.622375876Z �[34m│�[0m     ╷
2024-02-09T15:53:00.622379034Z �[34m│�[0m 245 │           width:  var(--tooltip-exaggerated-shadow-size);
2024-02-09T15:53:00.622387908Z �[34m│�[0m     │                ^
2024-02-09T15:53:00.622391277Z �[34m│�[0m     ╵
2024-02-09T15:53:00.622394760Z �[34m│�[0m   stylesheets/components/tooltip.scss 245:16  root stylesheet