Update beam_PostCommit_Python_Xlang_Gcp_Dataflow.yml (#36015)

Author: liferoad

.github/workflows/beam_PostCommit_Python_Xlang_Gcp_Dataflow.yml

@@ -57,7 +57,7 @@ jobs:
       (github.event_name == 'schedule' && github.repository == 'apache/beam') ||
       github.event.comment.body == 'Run Python_Xlang_Gcp_Dataflow PostCommit'
     runs-on: [self-hosted, ubuntu-20.04, main]
-    timeout-minutes: 180
+    timeout-minutes: 240
     name: ${{ matrix.job_name }} (${{ matrix.job_phrase }})
     strategy:
       matrix:
@@ -95,4 +95,4 @@ jobs:
           commit: '${{ env.prsha || env.GITHUB_SHA }}'
           comment_mode: ${{ github.event_name == 'issue_comment'  && 'always' || 'off' }}
           files: '**/pytest*.xml'
-          large_files: true
+          large_files: true