Don't clear Django global apps cache

What is in this MR

Certain modifications have been made to ensure that the do_pending_operations function is called on models when necessary. Additionally, only the Django model fields cache related to Baserow dynamic models is cleared.

This is essential for maintaining a distinct global Django apps registry that contains all the "static" models separate from Baserow "dynamic" ones. Despite this separation, it still provides all the advantages of Django ORM for the dynamically created models.

How to test this MR

• Verify dynamic models still behave as expected
• Verify that concurrent requests can be handled without errors on related models (please contact me or add a comment below if you need instructions to setup the environment to test this)
• Check the implemented logic. These are very delicate changes and it's important to double-check that everything makes sense.
• Verify there are no memory leaks in this implementationd

Merge Request Checklist

• changelog.md has been updated if required.
• New/updated Premium/Enterprise features are separated correctly in the premium or enterprise folder
• The latest Chrome and Firefox have been used to test any new frontend features
• Documentation has been updated
• Quality Standards are met
• Performance: tables are still fast with 100k+ rows, 100+ field tables
• The redoc API pages have been updated for any REST API changes
• Our custom API docs are updated for changes to endpoints accessed via api tokens
• The UI/UX has been updated following UI Style Guide