A few tweaks

frontend/src/pages/organization/AppConnections/AppConnectionsPage/components/AppConnectionForm/MsSqlConnectionForm.tsx

@@ -152,7 +152,7 @@ export const MsSqlConnectionForm = ({ appConnection, onSubmit }: Props) => {
                     <div>
                       <Select
                         isDisabled={!isAllowed}
-                        value={value}
+                        value={value as string}
                         onValueChange={onChange}
                         className="w-full border border-mineshaft-500"
                         dropdownContainerClassName="max-w-none"

frontend/src/pages/organization/AppConnections/AppConnectionsPage/components/AppConnectionForm/MySqlConnectionForm.tsx

@@ -149,7 +149,7 @@ export const MySqlConnectionForm = ({ appConnection, onSubmit }: Props) => {
                     <div>
                       <Select
                         isDisabled={!isAllowed}
-                        value={value}
+                        value={value as string}
                         onValueChange={onChange}
                         className="w-full border border-mineshaft-500"
                         dropdownContainerClassName="max-w-none"

frontend/src/pages/organization/AppConnections/AppConnectionsPage/components/AppConnectionForm/OracleDBConnectionForm.tsx

@@ -149,7 +149,7 @@ export const OracleDBConnectionForm = ({ appConnection, onSubmit }: Props) => {
                     <div>
                       <Select
                         isDisabled={!isAllowed}
-                        value={value}
+                        value={value as string}
                         onValueChange={onChange}
                         className="w-full border border-mineshaft-500"
                         dropdownContainerClassName="max-w-none"

frontend/src/pages/organization/AppConnections/AppConnectionsPage/components/AppConnectionForm/PostgresConnectionForm.tsx

@@ -149,7 +149,7 @@ export const PostgresConnectionForm = ({ appConnection, onSubmit }: Props) => {
                     <div>
                       <Select
                         isDisabled={!isAllowed}
-                        value={value}
+                        value={value as string}
                         onValueChange={onChange}
                         className="w-full border border-mineshaft-500"
                         dropdownContainerClassName="max-w-none"

frontend/src/pages/organization/AppConnections/AppConnectionsPage/components/AppConnectionForm/shared/sql-connection-schemas.ts

@@ -1,7 +1,7 @@
 import { z } from "zod";
 
 export const BaseSqlUsernameAndPasswordConnectionSchema = z.object({
-  gatewayId: z.string().optional(),
+  gatewayId: z.string().nullable().optional(),
   host: z.string().trim().min(1, "Host required"),
   port: z.coerce.number().default(5432),
   database: z.string().trim().min(1, "Database required").default("default"),