Avoid warning from providing both version inputs.

Author: desrosj

.github/workflows/reusable-test-core-build-process.yml

@@ -78,7 +78,7 @@ jobs:
         uses: actions/setup-node@cdca7365b2dadb8aad0a33bc7601856ffabcc48e # v4.3.0
         with:
           node-version: ${{ inputs.node-version }}
-          node-version-file: '.nvmrc'
+          node-version-file: ${{ inputs.node-version == '' && '.nvmrc' || '' }}
           cache: npm
 
       - name: Log debug information

.github/workflows/reusable-test-gutenberg-build-process.yml

@@ -71,7 +71,7 @@ jobs:
         uses: actions/setup-node@cdca7365b2dadb8aad0a33bc7601856ffabcc48e # v4.3.0
         with:
           node-version: ${{ inputs.node-version }}
-          node-version-file: '.nvmrc'
+          node-version-file: ${{ inputs.node-version == '' && '.nvmrc' || '' }}
           cache: npm
           cache-dependency-path: |
             package-lock.json