ci: Fix testflight upload (#6711)

Run prepare-package script for uploading to testflight to fix SPM
resolving issues.

Author: philipphofmann

.github/workflows/testflight.yml

@@ -46,6 +46,16 @@ jobs:
         with:
           bundler-cache: true
 
+      # As the DistributionSample project uses local SPM, xcodebuild resolves SPM dependencies for all
+      # sample projects. The Package.swift references binary targets, which in release branch commits points
+      # to non-existent download URLs. This creates chicken-egg failures when building these sample apps for
+      # a release commit build. When building these sample apps for a release commit, xcodebuild tries to
+      # resolve all SPM dependencies, including the binary targets pointing to these non-existent URLs.  The
+      # sample projects don't use SPM for including Sentry. Only the DistributionSample uses local SPM.
+      # Therefore, we only keep the local DistributionSample reference in the Package.swift as a workaround.
+      - name: Only keep distribution lib and target in Package.swift
+        run: ./scripts/prepare-package.sh --only-keep-distribution true
+
       - run: make init-ci-build
       - run: make xcode-ci