Allow specifying primary registry in include-install-pnpm.yaml (microsoft#25540)

## Description

Follow-up to microsoft#25535 that allows specifying the primary registry in
`include-install-pnpm.yaml` so that the telemetry stage upload template
can reference the feed we use to install internal packages.

Test run
[here](https://dev.azure.com/fluidframework/internal/_build/results?buildId=357059&view=logs&j=7ef2f12f-27d7-5730-657b-d3ad5f630362&t=9da23dd1-2e0f-578e-ea27-ee9162e0f22c).

Co-authored-by: Abram Sanderson <absander@microsoft.com>

Author: 2 people

tools/pipelines/templates/include-install-pnpm.yml

@@ -27,6 +27,10 @@ parameters:
   type: string
   default: $(Agent.TempDirectory)/.npmrc
 
+- name: primaryRegistry
+  type: string
+  default: $(ado-feeds-primary-registry)
+
 steps:
 - ${{ if eq(parameters.enableCache, true) }}:
   - task: Cache@2
@@ -69,13 +73,13 @@ steps:
         echo "##vso[task.setvariable variable=registryType]private"
       fi
   env:
-    NPM_REGISTRY: $(ado-feeds-primary-registry)
+    NPM_REGISTRY: ${{ parameters.primaryRegistry }}
     NPM_CONFIG_USERCONFIG: ${{ parameters.userNpmrcPath}}
     # We should leverage the primary npm registry to install pnpm as well. However, ADO artifacts feeds do not implement
     # the full npm registry API including a route that corepack uses to get package metadata--the version route here:
     # https://github.com/nodejs/corepack/blob/bc13d40037d0b1bfd386e260ae741f55505b5c7c/sources/npmRegistryUtils.ts#L32
     # Thus installing pnpm from an ADO feed using corepack is not possible at time of writing.
-    # COREPACK_NPM_REGISTRY: $(ado-feeds-primary-registry)
+    # COREPACK_NPM_REGISTRY: ${{ parameters.primaryRegistry }}
 
 # Authenticate to npm feed if required
 - task: npmAuthenticate@0

tools/pipelines/templates/include-upload-stage-telemetry.yml

@@ -49,6 +49,7 @@ stages:
     - template: /tools/pipelines/templates/include-install-pnpm.yml@self
       parameters:
         buildDirectory: $(Build.SourcesDirectory)
+        primaryRegistry: $(ado-feeds-ff-download-only)
 
     - task: Bash@3
       displayName: 'Install dependencies'