refactor(schema): reorganize IndexField and related types (#22439)

## Summary

Querying `indexMetadatas { indexFieldMetadatas { ... } }` on the
`/metadata` GraphQL endpoint fails with a 500:

> Nest could not find IndexFieldMetadataDTOAuthorizer element (this
provider does not
> exist in the current context)

The `@CursorConnection('indexFieldMetadatas', ...)` decorator on
`IndexMetadataDTO` makes nestjs-query auto-generate a relation resolver
that injects an authorizer for `IndexFieldMetadataDTO`. That authorizer
is never provided, because the DTO was never registered as a resolver in
`IndexMetadataModule` — so the field has been broken since it was
introduced in #7162.

Since the working, DataLoader-backed `indexFieldMetadataList` field
already exposes the same data (and is what the frontend uses), this PR
removes the dead connection instead of wiring up the authorizer.

## Changes

- Remove `@CursorConnection('indexFieldMetadatas', ...)` from
`IndexMetadataDTO`
- Regenerate frontend metadata GraphQL types
(`twenty-front/src/generated-metadata`)
- Regenerate client SDK metadata schema/types
(`twenty-client-sdk/src/metadata/generated`)

## Notes

- Not a breaking change in practice: the removed field always threw, so
no consumer can have been relying on it. Callers now get a standard
GraphQL validation error suggesting `indexFieldMetadataList` instead of
an internal server error.
- Verified locally: the failing query now returns `Cannot query field
"indexFieldMetadatas" on type "Index". Did you mean
"indexFieldMetadataList"?` and `indexFieldMetadataList` continues to
work.

Fixes [sonarly issue #54098](https://sonarly.com/issue/54098?type=bug)

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packages/twenty-server/src/engine/metadata-modules/index-metadata/dtos/index-metadata.dto.ts

@@ -24,7 +24,6 @@ import {
 
 import { UUIDScalarType } from 'src/engine/api/graphql/workspace-schema-builder/graphql-types/scalars';
 import { IsValidMetadataName } from 'src/engine/decorators/metadata/is-valid-metadata-name.decorator';
-import { IndexFieldMetadataDTO } from 'src/engine/metadata-modules/index-metadata/dtos/index-field-metadata.dto';
 import { IndexType } from 'src/engine/metadata-modules/index-metadata/types/indexType.types';
 import { ObjectMetadataDTO } from 'src/engine/metadata-modules/object-metadata/dtos/object-metadata.dto';
 
@@ -46,7 +45,6 @@ registerEnumType(IndexType, {
   maxResultsSize: 1000,
 })
 @CursorConnection('objectMetadata', () => ObjectMetadataDTO)
-@CursorConnection('indexFieldMetadatas', () => IndexFieldMetadataDTO)
 export class IndexMetadataDTO {
   @IsUUID()
   @IsNotEmpty()