fix(ci): remove net48 build target from unit-tests, skip integration for dependabot

unit-tests.yml: The publishable project targets netstandard2.0 only
(D009/F047), so the net48 build matrix entry fails. PS 5.1 loads
netstandard2.0 assemblies on .NET Framework 4.8, so the PS 5.1 Pester
tests now use the netstandard2.0 artifact.

integration-tests.yml: Skip entire workflow for dependabot PRs since
integration tests on the self-hosted runner are expensive and dependency
bumps don't warrant full end-to-end testing. Also updates dotnet SDK
from 9.0.x to 10.0.x for consistency.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.github/workflows/unit-tests.yml

@@ -15,8 +15,6 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - os: windows-latest
-            framework: net48
           - os: windows-latest
             framework: netstandard2.0
           - os: ubuntu-latest
@@ -53,7 +51,7 @@ jobs:
         include:
           - os: windows-latest
             ps_version: '5.1'
-            framework: net48
+            framework: netstandard2.0
             artifact_os: windows-latest
             shell: powershell
           - os: windows-latest