Fail if the emulator doesn't start (#3777)

We had continueOnError set to true so if the emulator failed to start we would still try to run the tests which all fail but take a long time to run.  The timeout for this step is about 10mins of trying so that should be enough time and so we also don't really need another retry step.

Co-authored-by: Wes Haggard <weshaggard@users.noreply.github.com>

eng/common/pipelines/templates/steps/cosmos-emulator.yml

@@ -22,15 +22,3 @@ steps:
         -Stage "Launch"
       pwsh: true
     displayName: Launch Public Cosmos DB Emulator
-    continueOnError: true
-
-  - task: Powershell@2
-    inputs:
-      filePath: $(Build.SourcesDirectory)/eng/common/scripts/Cosmos-Emulator.ps1
-      arguments: >
-        -EmulatorMsiUrl "${{ parameters.EmulatorMsiUrl }}"
-        -StartParameters "${{ parameters.StartParameters }}"
-        -Stage "Launch"
-      pwsh: true
-    displayName: Retry Launch of Public Cosmos DB Emulator
-    condition: failed()