docs: Provide feedback when cloning submodules (#9448)

<!-- Clearly explain the need for these changes: -->

### Changes 🏗️
Added `--progress` to the submodule update, so that cloning progress can
be tracked and does not appear to hang.
<!-- Concisely describe all of the changes made in this pull request:
-->

### Checklist 📋

#### For code changes:
- [x] No code change, just docs.
 

<details>
  <summary>Example test plan</summary>
  
  - [ ] Create from scratch and execute an agent with at least 3 blocks
- [ ] Import an agent from file upload, and confirm it executes
correctly
  - [ ] Upload agent to marketplace
- [ ] Import an agent from marketplace and confirm it executes correctly
  - [ ] Edit an agent from monitor, and confirm it executes correctly
</details>

#### For configuration changes:
- [x] No configuration change, just docs.
 

<details>
  <summary> Provide feedback when cloning submodules </summary>

  -  now updating submodules shows the cloning repo's progress
 
</details>

Co-authored-by: Your Name <you@example.com>

autogpt_platform/README.md

@@ -22,7 +22,7 @@ To run the AutoGPT Platform, follow these steps:
 
 2. Run the following command:
    ```
-   git submodule update --init --recursive
+   git submodule update --init --recursive --progress
    ```
    This command will initialize and update the submodules in the repository. The `supabase` folder will be cloned to the root directory.
 

docs/content/platform/getting-started.md

@@ -77,7 +77,7 @@ To run the backend services, follow these steps:
 
 * Within the repository, clone the submodules and navigate to the `autogpt_platform` directory:
   ```bash
-   git submodule update --init --recursive
+   git submodule update --init --recursive --progress
    cd autogpt_platform
   ```
   This command will initialize and update the submodules in the repository. The `supabase` folder will be cloned to the root directory.