Remove references to obsolete storage account variables (#56100)

Author: mmitche

.azure/pipelines/blazor-daily-tests.yml

@@ -7,7 +7,6 @@
 # We just need one Windows machine because all it does is trigger SauceLabs.
 variables:
   - ${{ if ne(variables['System.TeamProject'], 'public') }}:
-      - group: DotNet-MSRC-Storage
       - group: AzureDevOps-Artifact-Feeds-Pats
   - name: SAUCE_CONNECT_DOWNLOAD_ON_INSTALL
     value: true

.azure/pipelines/signalr-daily-tests.yml

@@ -6,7 +6,6 @@
 
 variables:
   - ${{ if ne(variables['System.TeamProject'], 'public') }}:
-    - group: DotNet-MSRC-Storage
     - group: AzureDevOps-Artifact-Feeds-Pats
   - template: /eng/common/templates-official/variables/pool-providers.yml@self