fix: Use environment variables for script inputs in all workflows

[Mrtenz]

Instead of adding script inputs in the bash script directly, we can use environment variables.

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Note

Replaces inline input interpolation with environment variables and step outputs across actions/workflows, simplifying scripts and standardizing parameter handling (and removes a redundant step in PR line check).

• Workflows:
  • create-release-pr / update-release-changelog / stable-sync / main / lint-workflows: Move script arguments and references to env vars; pass inputs via env and consume $VARS in runs.
  • pr-line-check: Remove separate base-branch resolution step; set BASE_BRANCH via env; read change counts and thresholds from env in github-script.
• Composite Actions:
  • checkout-and-setup: Validate is-high-risk-environment via IS_HIGH_RISK_ENVIRONMENT env var.
  • configure-keystore: Use TARGET and AWS_REGION env vars when selecting secret and fetching from AWS.
  • setup-e2e-env: Use env vars for Android AVD/image params, Yarn install command via a step output, Foundry and Xcode versions via env.
  • upload-s3: Use UPLOAD_PATH and S3_BUCKET env vars for S3 copy commands.

^{Written by Cursor Bugbot for commit 895a557. This will update automatically on new commits. Configure here.}

[Mrtenz]

I'm not sure how nick-fields/retry uses the command below, so added this just in case.

[cryptodev-2s]

LGTM!