[github actions] refactor and fix cherry pick actions (#140499)

This PR makes the following changes:

1. Remove dependency on [peters/evans package](https://github.com/marketplace/actions/create-pull-request)<br>
The market place action introduces overheads that don't properly consume tokens. e.g. :[failed workflow that says token is not supplied](https://github.com/flutter/flutter/actions/runs/7282529195/job/19845096943)
This PR changes the market place action to git commands that we have full control over, provides better error msg for debug, and properly consumes token.

2. Align usage of tokens:<br>
All tokens in the workflow now uses flutter actions bot PAT token. From experiments, a mixed usage of different tokens in different steps sometimes cause the workflow to fail on authentication.

Tested: Tested with [a similar workflow on my personal repository](https://github.com/XilaiZhang/miscellaneous-side-project/blob/master/.github/workflows/easy-cp.yml), and it produces the [expected cherry pick PR as end result](https://github.com/flutter/flutter/pull/140497)

.github/workflows/easy-cp.yml

@@ -32,8 +32,8 @@ jobs:
       - name: Checkout Flutter Repo
         uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11
         with:
-          repository: flutter/flutter
-          token: ${{ github.token }}
+          repository: flutteractionsbot/flutter
+          token: ${{ secrets.FLUTTERACTIONSBOT_CP_TOKEN }}
           path: flutter
           ref: master
           # Checkout all history commits on master branch, so that the cp commit is a known object
@@ -45,9 +45,10 @@ jobs:
         run: |
           git config user.name "GitHub Actions Bot"
           git config user.email "<>"
-          git fetch origin $RELEASE_BRANCH
-          git fetch origin master
-          git checkout -b $RELEASE_BRANCH --track origin/$RELEASE_BRANCH
+          git remote add upstream https://github.com/flutter/flutter.git
+          git fetch upstream $RELEASE_BRANCH
+          git fetch upstream master
+          git checkout -b cp-${CHANNEL}-${COMMIT_SHA} --track upstream/$RELEASE_BRANCH
           git cherry-pick $COMMIT_SHA
       # TODO(xilaizhang): remove this step once the template is available on release branches.
       - name: Get CP Template
@@ -55,16 +56,13 @@ jobs:
           curl -o PULL_REQUEST_CP_TEMPLATE.md https://raw.githubusercontent.com/flutter/flutter/master/.github/PR_TEMPLATE/PULL_REQUEST_CP_TEMPLATE.md
       - name: Create PR on CP success
         if: ${{ steps.attempt-cp.conclusion == 'success' }}
-        uses: peter-evans/create-pull-request@153407881ec5c347639a548ade7d8ad1d6740e38
-        with:
-          base: ${{ env.RELEASE_BRANCH }}
-          branch: cp-${{ env.CHANNEL }}-${{ env.COMMIT_SHA }}
-          path: flutter
-          token: ${{ secrets.FLUTTERACTIONSBOT_CP_TOKEN }}
-          labels: |
-            cp: review
-          title: '[${{ env.CHANNEL }}-cherrypick] cherrypicks commit ${{ env.COMMIT_SHA }} from PR ${{ github.event.pull_request.title }}'
-          body-path: PULL_REQUEST_CP_TEMPLATE.md
+        working-directory: ./flutter
+        run: |
+          git push -u origin cp-${CHANNEL}-${COMMIT_SHA}
+          gh pr create --title "[CP-${CHANNEL}]${PR_TITLE}" --body-file ../PULL_REQUEST_CP_TEMPLATE.md --base ${RELEASE_BRANCH} --label "cp: review" --repo flutter/flutter
+        env:
+          GITHUB_TOKEN: ${{ secrets.FLUTTERACTIONSBOT_CP_TOKEN }}
+          PR_TITLE: ${{ github.event.pull_request.title }}
       - name: Leave Comment on CP failure
         if: ${{ failure() && steps.attempt-cp.conclusion == 'failure' }}
         run: |
@@ -72,4 +70,4 @@ jobs:
           FAILURE_MSG+="You will need to create the PR manually. See [the cherrypick wiki](https://github.com/flutter/flutter/wiki/Flutter-Cherrypick-Process) for more info."
           gh pr comment ${{ github.event.pull_request.number }} -R flutter/flutter -b "${FAILURE_MSG}"
         env:
-          GITHUB_TOKEN: ${{ secrets.FLUTTERMIRRORINGBOT_TOKEN }}
+          GITHUB_TOKEN: ${{ secrets.FLUTTERACTIONSBOT_CP_TOKEN }}