Harden primer package caching against possible race condition

Refs #9925 (comment)

Author: jacobtylerwalls

.github/workflows/primer_run_main.yaml

@@ -78,7 +78,8 @@ jobs:
             ${{ runner.os }}-${{ matrix.python-version }}-${{
             steps.commitstring.outputs.commitstring }}-primer
       - name: Regenerate cache
-        if: steps.cache-projects.outputs.cache-hit != 'true'
+        # Presence of colorama is a heuristic for the env having all packages
+        if: steps.cache-projects.outputs.cache-hit != 'true' || ! pip show colorama
         run: |
           . venv/bin/activate
           python tests/primer/__main__.py prepare --clone

.github/workflows/primer_run_pr.yaml

@@ -147,7 +147,8 @@ jobs:
             ${{ runner.os }}-${{ matrix.python-version }}-${{
             steps.commitstring.outputs.commitstring }}-primer
       - name: Regenerate cache
-        if: steps.cache-projects.outputs.cache-hit != 'true'
+        # Presence of colorama is a heuristic for the env having all packages
+        if: steps.cache-projects.outputs.cache-hit != 'true' || ! pip show colorama
         run: |
           . venv/bin/activate
           python tests/primer/__main__.py prepare --clone