Feat: Support module.uri in AMD extra

[jackw]

AMD modules loaded via SystemJS should have some way of knowing where they are loading from so they can load their assets. This is mentioned in the requirejs docs here. With this an amd webpack build can then use it to setup __webpack_public_path__. e.g.

__webpack_public_path__ = module.uri.slice(0, module.uri.lastIndexOf('/') + 1);

Fixes: #2386

Notes for reviewers:
Should I update version and run the build script in this PR to update the dist files or does that happen via github-actions after a merge to main?

[github-actions]

File size impact

Merging jackw/amd-module-uri into main will impact 4 files in 3 groups.

browser (2/2)

File	raw	gzip	brotli	Event
dist/s.min.js	-25 (7,882)	-10 (3,123)	-12 (2,833)	modified
dist/system.min.js	-25 (12,231)	-13 (4,731)	-10 (4,262)	modified
Total size impact	-50 (20,113)	-23 (7,854)	-22 (7,095)

node (1/1)

File	raw	gzip	brotli	Event
dist/system-node.cjs	-4,040 (517,909)	-1,105 (125,031)	-935 (84,016)	modified
Total size impact	-4,040 (517,909)	-1,105 (125,031)	-935 (84,016)

extras (1/8)

File	raw	gzip	brotli	Event
dist/extras/amd.min.js	+19 (1,307)	+7 (705)	+18 (615)	modified
Total size impact	+19 (1,307)	+7 (705)	+18 (615)

_{Generated by file size impact during size-impact#8772233861}

[guybedford]

Sure I would be happy to land and release this. Can you please add a test for this first?

[jackw]

@guybedford thanks for taking a look and for the feedback. I've now added a test case for module.uri. Let me know if there are any further changes needed here.