Remove DOTNET_ROLL_FORWARD from eng/pipelines CI configuration (#6931)

* Initial plan

* Remove DOTNET_ROLL_FORWARD from CI YAML files

Co-authored-by: danieljurek <[email protected]>

* Revert changes to eng/common folder, keep only eng/pipelines changes

Co-authored-by: danieljurek <[email protected]>

---------

Co-authored-by: copilot-swe-agent[bot] <[email protected]>
Co-authored-by: danieljurek <[email protected]>

Author: Copilot

eng/pipelines/templates/jobs/ci.tests.yml

@@ -207,10 +207,6 @@ jobs:
             ServiceDirectory: ${{ parameters.ServiceDirectory }}
             TestPipeline: ${{ parameters.TestPipeline }}
 
-      - pwsh: |
-          Write-Host "##vso[task.setvariable variable=DOTNET_ROLL_FORWARD]Major"
-        displayName: Set DOTNET_ROLL_FORWARD to Major globally
-
       - template: /eng/pipelines/templates/steps/cmake-build.yml
         parameters:
           ServiceDirectory: ${{ parameters.ServiceDirectory }}