Explicitly set workspaceId column as uuid type to ease pg LEFT JOIN (#15430)

Pg scan was redundant because historically the workspaceId was
`varchar`, even though below migration won't change that we had a look
to workspaceId col declaration across the codebase

packages/twenty-server/src/engine/core-modules/key-value-pair/key-value-pair.entity.ts

@@ -67,7 +67,7 @@ export class KeyValuePairEntity {
   @JoinColumn({ name: 'workspaceId' })
   workspace: Relation<WorkspaceEntity>;
 
-  @Column({ nullable: true })
+  @Column({ nullable: true, type: 'uuid' })
   workspaceId: string | null;
 
   @Field(() => String)