[feat] Add updateRemoteServer endpoint (#5148)

## Context
#4765 

Following investigations
([#5083](https://github.com/twentyhq/twenty/issues/5083)) we decided to
restrict updates of server from which zero tables have been synchronized
only

## How was it tested
Locally with /metadata
1. Updating a database that already has synchronized tables
<img width="1072" alt="Capture d’écran 2024-04-24 à 16 16 05"
src="https://github.com/twentyhq/twenty/assets/51697796/f9a84c34-2dcd-4f3c-b0bc-b710abae5021">

2. Updating a database that has no synchronized tables
<img width="843" alt="Capture d’écran 2024-04-24 à 16 17 28"
src="https://github.com/twentyhq/twenty/assets/51697796/f320fe03-a6bc-4724-bcd0-4e89d3ac31f5">
+ tested that the connection works well

packages/twenty-server/src/engine/metadata-modules/remote-server/remote-table/remote-table.service.ts

@@ -74,14 +74,14 @@ export class RemoteTableService {
       throw new NotFoundException('Remote server does not exist');
     }
 
-    const currentRemoteTableDistantNames = (
-      await this.remoteTableRepository.find({
-        where: {
-          remoteServerId: id,
-          workspaceId,
-        },
-      })
-    ).map((remoteTable) => remoteTable.distantTableName);
+    const currentRemoteTables = await this.findCurrentRemoteTablesByServerId({
+      remoteServerId: id,
+      workspaceId,
+    });
+
+    const currentRemoteTableDistantNames = currentRemoteTables.map(
+      (remoteTable) => remoteTable.distantTableName,
+    );
 
     const tablesInRemoteSchema =
       await this.fetchTablesFromRemoteSchema(remoteServer);
@@ -95,6 +95,21 @@ export class RemoteTableService {
     }));
   }
 
+  public async findCurrentRemoteTablesByServerId({
+    remoteServerId,
+    workspaceId,
+  }: {
+    remoteServerId: string;
+    workspaceId: string;
+  }) {
+    return this.remoteTableRepository.find({
+      where: {
+        remoteServerId,
+        workspaceId,
+      },
+    });
+  }
+
   public async syncRemoteTable(input: RemoteTableInput, workspaceId: string) {
     if (!input.schema) {
       throw new BadRequestException(