fix: sync devtools frontend mime types with upstream

[nornagon]

Description of Change

Fixes #25778.

This updates the function to match
https://source.chromium.org/chromium/chromium/src/+/master:chrome/browser/ui/webui/devtools_ui_data_source.cc;l=52;drc=2de0b2cfe26853bda417346c8a6e6538a06780d8.

Checklist

• PR description included and stakeholders cc'd
• npm test passes
• tests are changed or added
• relevant documentation is changed or added
• PR title follows semantic commit guidelines
• PR release notes describe the change in a way relevant to app developers, and are capitalized, punctuated, and past tense.

Release Notes

Notes: Fixed the pretty-print JavaScript feature in DevTools not functioning correctly.

[codebytere]

think you're missing a header:

inlines-hidden -Wno-deprecated-declarations -c ../../electron/shell/browser/ui/devtools_ui.cc -o obj/electron/electron_lib/devtools_ui.o
../../electron/shell/browser/ui/devtools_ui.cc:25:21: error: no member named 'StrCat' in namespace 'base'
  return GURL(base::StrCat({content::kChromeDevToolsScheme,
              ~~~~~~^
1 error generated.

[nornagon]

whups, fixed locally and forgot to push.

[release-clerk]

Release Notes Persisted

Fixed the pretty-print JavaScript feature in DevTools not functioning correctly.

[MarshallOfSound]

/trop run backport

[trop]

The backport process for this PR has been manually initiated, here we go! :D

[trop]

I have automatically backported this PR to "11-x-y", please check out #27102