Activity as standard object (#6219)

In this PR I layout the first steps to migrate Activity to a traditional
Standard objects

Since this is a big transition, I'd rather split it into several
deployments / PRs

<img width="1512" alt="image"
src="https://github.com/user-attachments/assets/012e2bbf-9d1b-4723-aaf6-269ef588b050">

---------

Co-authored-by: Charles Bochet <charles@twenty.com>
Co-authored-by: bosiraphael <71827178+bosiraphael@users.noreply.github.com>
Co-authored-by: Weiko <corentin@twenty.com>
Co-authored-by: Faisal-imtiyaz123 <142205282+Faisal-imtiyaz123@users.noreply.github.com>
Co-authored-by: Prateek Jain <prateekj1171998@gmail.com>

packages/twenty-front/src/generated/graphql.tsx

@@ -250,6 +250,7 @@ export enum FieldMetadataType {
   Rating = 'RATING',
   RawJson = 'RAW_JSON',
   Relation = 'RELATION',
+  RichText = 'RICH_TEXT',
   Select = 'SELECT',
   Text = 'TEXT',
   Uuid = 'UUID'