[release/dev17.14] [release/dev18.0] Fix parameter syntax in pipeline definition (#81297)

Backport of #81286 to release/dev17.14

/cc @JoeRobich @github-actions[bot]

## Customer Impact

## Regression

- [ ] Yes
- [ ] No

[If yes, specify when the regression was introduced. Provide the PR or
commit if known.]

## Testing

[How was the fix verified? How was the issue missed previously? What
tests were added?]

## Risk

[High/Medium/Low. Justify the indication by mentioning how risks were
measured and addressed.]

---------

Co-authored-by: Jan Jones <janjones@microsoft.com>

Author: github-actions[bot]

azure-pipelines-official.yml

@@ -308,10 +308,10 @@ extends:
                        -binaryLog
                        -configuration $(BuildConfiguration)
                        -officialBuildId $(Build.BuildNumber)
-                       -officialSkipTests $(SkipTests)
+                       -officialSkipTests ${{ parameters.SkipTests }}
                        -officialSkipApplyOptimizationData ${{ parameters.SkipApplyOptimizationData }}
                        -officialSourceBranchName $(SourceBranchName)
-                       -officialIbcDrop $(IbcDrop)
+                       -officialIbcDrop ${{ parameters.IbcDrop }}
                        -officialVisualStudioDropAccessToken $(_DevDivDropAccessToken)
                        /p:RepositoryName=$(Build.Repository.Name)
                        /p:VisualStudioDropName=$(VisualStudio.DropName)
@@ -351,7 +351,7 @@ extends:
             testResultsFiles: '$(Build.SourcesDirectory)\artifacts\TestResults\$(BuildConfiguration)\*.xml'
             mergeTestResults: true
             testRunTitle: 'Unit Tests'
-          condition: and(succeededOrFailed(), ne(variables['SkipTests'], 'true'))
+          condition: and(succeededOrFailed(), ${{ not(parameters.SkipTests) }})
 
       # Publish to Build Asset Registry
       - template: /eng/common/templates-official/job/publish-build-assets.yml@self