Run package network tests in integration matrix

Enable the guarded package-manager network suites in the existing integration step for every OS and Python version, and remove the separate manual workflow.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot-Session: edcaaa35-9a42-4351-98fa-55bcf8f1968e

Author: edvilme

.github/workflows/package-manager-network-check.yml

@@ -252,6 +252,8 @@ jobs:
     name: Integration Tests
     runs-on: ${{ matrix.os }}
     needs: [smoke-tests]
+    env:
+      VSC_PYTHON_PACKAGE_NETWORK_TEST: '1'
     strategy:
       fail-fast: false
       matrix:

.github/workflows/pr-check.yml

@@ -253,6 +253,8 @@ jobs:
     name: Integration Tests
     runs-on: ${{ matrix.os }}
     needs: [smoke-tests]
+    env:
+      VSC_PYTHON_PACKAGE_NETWORK_TEST: '1'
     strategy:
       fail-fast: false
       matrix: