build: upload prototype source maps under the embedded release

Prototype builds set `VERSION_SHORT` to `pr_or_branch`, so the app's runtime
Sentry release is `<app_identifier>@<pr_or_branch>+<build_number>` (e.g.
`com.jetpack.alpha@PR #25800+33210`). The source-map uploads were keyed to
`release_version_current` (the marketing version, e.g. `27.0`), which never
matches that runtime release — so prototype-build events stayed unsymbolicated.

Pass `pr_or_branch` as the release version for both the GutenbergKit and the
existing React Native source-map uploads on prototype builds. This fixes
GutenbergKit symbolication and also a pre-existing gap in the React Native
prototype upload.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: dcalhoun

fastlane/lanes/build.rb

@@ -536,16 +536,22 @@ def build_and_upload_prototype_build(scheme:, output_app_name:, firebase_app_con
       path: lane_context[SharedValues::DSYM_OUTPUT_PATH]
     )
 
+    # Source maps must be uploaded under the SAME release the app embeds at
+    # runtime. Prototype builds set `VERSION_SHORT` to `pr_or_branch` (not the
+    # marketing version), so the Sentry release is
+    # `<app_identifier>@<pr_or_branch>+<build_number>`. Uploading under
+    # `release_version_current` here would not match the runtime event, leaving
+    # frames unsymbolicated.
     upload_gutenberg_sourcemaps(
       sentry_project_slug: sentry_project_slug,
-      release_version: release_version_current,
+      release_version: pr_or_branch,
       build_version: build_number,
       app_identifier: app_identifier
     )
 
     upload_gutenberg_kit_sourcemaps(
       sentry_project_slug: sentry_project_slug,
-      release_version: release_version_current,
+      release_version: pr_or_branch,
       build_version: build_number,
       app_identifier: app_identifier
     )