Revert "CI: Run benchmarks if PR is labeled with "run/benchmark" (#2958)"

This reverts commit ecefd53.

Author: seisman

.github/workflows/benchmarks.yml

@@ -12,9 +12,8 @@ on:
     paths:
       - 'pygmt/**/*.py'
       - '.github/workflows/benchmarks.yml'
-  # Run in PRs but only if the PR has the 'run/benchmark' label
-  pull_request:
-    types: [ opened, reopened, labeled, synchronize ]
+  # Uncomment the 'pull_request' line below to trigger the workflow in PR
+  # pull_request:
   # `workflow_dispatch` allows CodSpeed to trigger backtest
   # performance analysis in order to generate initial data.
   workflow_dispatch:
@@ -29,7 +28,7 @@ concurrency:
 jobs:
   benchmarks:
     runs-on: ubuntu-22.04
-    if: github.repository == 'GenericMappingTools/pygmt' && (github.event_name != 'pull_request' || contains(github.event.pull_request.labels.*.name, 'run/benchmark'))
+    if: github.repository == 'GenericMappingTools/pygmt'
     defaults:
       run:
         shell: bash -l {0}