fix(inject): Skip non-base64 embedded sourcemaps

[nyan-left]

Description

When you bundle tools like terser or babel into a single JS file (common in browser-based IDEs or bundler workers), their minified code contains template literals that build //# sourceMappingURL=data:application/json;base64,... strings as output. After minification, these can land at the start of a line, and discover_sourcemaps_location treats them as real sourcemap directives.

The problem is the "base64" payload is actually just more JS code, so decoding fails and sourcemaps inject bails with Invalid embedded sourcemap, stopping the whole injection.

This changes the bail! to a warn! + continue, which matches how the injection flow already handles other non-fatal cases like missing sourcemaps, ambiguous paths, and unfound files. The file gets skipped and everything else processes normally.

Includes a test with a minimal fixture that reproduces the issue.

Issues

#3244

Legal Boilerplate

Look, I get it. The entity doing business as "Sentry" was incorporated in the State of Delaware in 2015 as Functional Software, Inc. and is gonna need some rights from me in order to utilize my contributions in this here PR. So here's the deal: I retain all rights, title and interest in and to my contributions, and by keeping this boilerplate intact I confirm that Sentry can use, modify, copy, and redistribute my contributions, under Sentry's choice of terms.

[loewenheim]

Very nice, thank you for the fix!

[loewenheim]

I took the liberty of adding a changelog entry.

[nyan-left]

Thanks @loewenheim ! :)