ci: make file changes check from master.

.gitea/workflows/on_called_build.yml

@@ -13,7 +13,6 @@ jobs:
         id: check-android-changes
         uses: tj-actions/changed-files@v46
         with:
-          base_sha: master
           files: |
             androidApp/src/**
             shared/src/commonMain/**

.gitea/workflows/on_pr.yml

@@ -33,7 +33,7 @@ jobs:
         id: check-translations-changes
         uses: tj-actions/changed-files@v46
         with:
-          base_sha: master
+          base_sha: ${{ github.event.pull_request.base.sha }}
           files: |
             androidApp/src/main/res/values/strings.xml
       - name: upload translation sources