ci(infra-3596): plumb runner_provider through run-e2e-api-specs.yml

Add runner_provider input to workflow_call so it propagates when this
workflow is uses:-called by other workflows, and switch the runs-on
expression from github.event.inputs.runner_provider (workflow_dispatch
only) to inputs.runner_provider (resolves for both call and dispatch).

The api-specs-ios job is currently if: false, so this is YAML-only with
no runtime effect — it brings the file in line with the rest of the
provider-aware iOS workflows.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: XxdpavelxX

.github/workflows/run-e2e-api-specs.yml

@@ -5,6 +5,12 @@ name: API Specs E2E Tests
 
 on:
   workflow_call:
+    inputs:
+      runner_provider:
+        description: Runner provider forwarded from the caller
+        required: false
+        type: string
+        default: current
   workflow_dispatch:
     inputs:
       runner_provider:
@@ -22,7 +28,7 @@ jobs:
   api-specs-ios:
     name: 'api-specs-ios'
     if: false
-    runs-on: ${{ github.event.inputs.runner_provider == 'namespace' && 'namespace-profile-metamask-ios-build' || 'macos-latest-xlarge' }}
+    runs-on: ${{ inputs.runner_provider == 'namespace' && 'namespace-profile-metamask-ios-build' || 'macos-latest-xlarge' }}
     continue-on-error: true
 
     env: