CI: Remove now unused godot-api-dump action

Its use was removed in b8480ffa21.

.github/actions/godot-api-dump/action.yml

@@ -1,25 +0,0 @@
-name: Dump Godot API
-description: Dump Godot API for GDExtension
-
-inputs:
-  bin:
-    description: The path to the Godot executable
-    required: true
-
-runs:
-  using: composite
-  steps:
-    # Dump GDExtension interface and API
-    - name: Dump GDExtension interface and API for godot-cpp build
-      shell: sh
-      run: |
-        ${{ inputs.bin }} --headless --dump-gdextension-interface --dump-extension-api
-        mkdir godot-api
-        cp -f gdextension_interface.h godot-api/
-        cp -f extension_api.json godot-api/
-
-    - name: Upload API dump
-      uses: ./.github/actions/upload-artifact
-      with:
-        name: godot-api-dump
-        path: ./godot-api/*