fix: Flutter caching issues in GitHub actions

[michalurbanek]

Currently there is an issue with subosito/flutter-action@v2 runner that is not hitting caches.
The issue is that each cache is stored under specific PR in Github and other PRs cannot find and hit the cache by the key - thus the caching was removed. Each Flutter SDK takes up to 1,5GB and consumes quite a lot from the 5GB space that we have for the caches.
It was all fine where we were using self hosted runners, but not worth while running in Github.
Downloading of the 1,5GB takes usually 10 seconds based on logs.

[Copilot]

Pull request overview

This PR addresses caching issues with the subosito/flutter-action@v2 GitHub Action runner where caches stored under specific PRs cannot be accessed by other PRs. The solution replaces the action's built-in caching with a manual actions/cache@v4 implementation that uses a cache key based on pubspec.lock.

Changes:

• Replaced built-in Flutter action caching with manual actions/cache@v4 implementation
• Removed cache-key and cache-path parameters from the Flutter action
• Added conditional execution to skip Flutter action when cache is hit

Comments suppressed due to low confidence (1)

.github/workflows/flutter_project_codecheck_android.yml:14

• Flutter version 3.38.5 does not exist. As of my knowledge cutoff in January 2025, the latest stable Flutter versions are in the 3.x range but do not reach 3.38.x. This appears to be a typo - it should likely be 3.3.8, 3.8.5, or another valid version. Please verify and correct the Flutter version.

  flutter_version: "3.38.5"

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.