Deprecation warning: create-github-app-token app-id should be client-id

## Problem

The `actions/create-github-app-token@v3` action warns on every run:

> Input 'app-id' has been deprecated with message: Use 'client-id' instead.

## Affected files

- `.github/workflows/dependabot-automerge.yml` (lines 28, 67)
- `.github/workflows/pull-from-bazel-build.yml` (line 50)

## Fix

Rename `app-id` to `client-id` in all three usages.