Improve FieldMetadataEntity defaultValue, settings and options typing (#13320)

# Introduction
Following https://github.com/twentyhq/twenty/pull/13264, this PR
introduces several `fieldMetadataEntity` typing enhancement suggestions.

Mainly any nullable field metadata entity properties are now either
nullable or defined.
Or never if field is dynamically required or not depending on the field
metadata type

This enhance DevX

## Standards

- field enum ( `MULTI_SELECT`, `SELECT`, `RATING` ) will never have
`options` set to `NULL` in db
- field `RELATION` or `MORH_RELATION` won't ever have its relation
fields set to `NULL` in db
- field of any type `settings`, even if possibly defined, can still be
`NULL` in db
- field of any type `defaultValue`, even if possibly defined, can still
be `NULL` in db

It coud be interesting to guard these standards by adding dedicated pg
constraints on each field

## TypesScript type tests
added coverage for each `settings`, `defaultValue`, and `options`
depending on the current `fieldMetadata`
Honestly I don' know if this typescript assertions test file is not
overkill, but regarding metadata staticness it might be very interesting
to have this guard

## Possible improvements
- We could type as `unknown` instead of "all" on `FieldMetadataType`
inferrance
- We still need to deprecate remaining duplicated entities such as
`Index/Field/MetadataInterface` etc not a huge refactor neither urgent

packages/twenty-shared/src/types/NullablePartial.ts

@@ -0,0 +1,3 @@
+export type NullablePartial<T> = {
+  [P in keyof T]: T[P] | null;
+};

packages/twenty-shared/src/types/index.ts

@@ -11,6 +11,7 @@ export type { ConfigVariableValue } from './ConfigVariableValue';
 export { ConnectedAccountProvider } from './ConnectedAccountProvider';
 export { FieldMetadataType } from './FieldMetadataType';
 export type { IsExactly } from './IsExactly';
+export type { NullablePartial } from './NullablePartial';
 export type { ObjectRecordsPermissions } from './ObjectRecordsPermissions';
 export type { ObjectRecordsPermissionsByRoleId } from './ObjectRecordsPermissionsByRoleId';
 export type { RestrictedFields } from './RestrictedFields';