Bumping to latest Vally release and standardising on package.json version (#2535)

The workflows were doing their own vally installs, which means that we had the potential for drift in the version of Vally being used. Now we do a npm ci and get the version from there, removing the ambiguity

.github/workflows/external-plugin-pr-quality-gates.yml

@@ -95,8 +95,8 @@ jobs:
       - name: Install GitHub Copilot CLI
         run: npm install -g @github/copilot
 
-      - name: Install @microsoft/vally
-        run: npm install @microsoft/vally
+      - name: Install node packages
+        run: npm ci
 
       - name: Run external plugin PR quality gates
         id: quality

.github/workflows/external-plugin-quality-gates.yml

@@ -36,8 +36,8 @@ jobs:
       - name: Install GitHub Copilot CLI
         run: npm install -g @github/copilot
 
-      - name: Install @microsoft/vally
-        run: npm install @microsoft/vally
+      - name: Install node packages
+        run: npm ci
 
       - name: Run external plugin quality gates
         id: quality