performance: don't fetch fields on action's initialization

[Paul-Bob]

Description

Fixes #3025

Fetch fields on each action request instead of on each action initialization.

Checklist:

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works

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[adrianthedev]

Can we add some tests for this, please?

[github-actions]

This PR has been merged into main. The functionality will be available in the next release.

Please check the release guide for more information.