Fix database event emission (#16759)

Fixes https://github.com/twentyhq/private-issues/issues/395


When calling `removeUserFromWorkspaceAndPotentiallyDeleteWorkspace` from
`user.service`,
```
        await workspaceMemberRepository.delete({
          userId: userWorkspace.userId,
        });
```
related database event is not emitted.

Same issue with update has been fixed
[here](https://github.com/twentyhq/twenty/pull/13287/changes)

The database event is not emitted because `await
eventSelectQueryBuilder.getOne()` in `workspace-delete-query-builder`
returns `null`. This happens because the `selectQueryBuilder` has no
entity—the database request is sent and the raw result is not `null`,
but the entity is `null`, causing the final result to be null.

It can be fixed the same way update has been fixed, updating the
`workspace-entity-manager`
- Pros : consistant with update but we should not forget to fix
softDelete and restore
- Cons : `workspace-entity-manager` is a copy of typeORM logic +
permission injection. Should it be more ?
 
Alternatively (as featured in this PR), it can be fixed by updating
computeEventSelectQueryBuilder, inspired by TypeORM's logic in
typeorm/query-builder/QueryBuilder.js at line 67.
- Pros : it fit with typeORM logic + It fixes all repository operations

packages/twenty-server/src/engine/twenty-orm/utils/compute-event-select-query-builder.util.ts

@@ -46,5 +46,14 @@ export const computeEventSelectQueryBuilder = <T extends ObjectLiteral>({
   eventSelectQueryBuilder.expressionMap.aliases = expressionMap.aliases;
   eventSelectQueryBuilder.setParameters(expressionMap.parameters);
 
+  if (
+    eventSelectQueryBuilder.expressionMap.selects.length === 0 &&
+    eventSelectQueryBuilder.expressionMap.mainAlias
+  ) {
+    eventSelectQueryBuilder.expressionMap.selects = [
+      { selection: eventSelectQueryBuilder.expressionMap.mainAlias.name },
+    ];
+  }
+
   return eventSelectQueryBuilder;
 };