revert: remove initialRowCount from copilot table creation

Copilot populates its own data after creating a table, so pre-creating
20 empty rows causes data to start at position 21 with empty rows above.
initialRowCount only makes sense for the manual UI creation flow.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

apps/sim/lib/copilot/tools/server/table/user-table.ts

@@ -229,7 +229,6 @@ export const userTableServerTool: BaseServerTool<UserTableArgs, UserTableResult>
               schema: args.schema,
               workspaceId,
               userId: context.userId,
-              initialRowCount: 20,
             },
             requestId
           )