fix: close timeout in ConditionalModule

When conditional module was used in integration
tests with jest, then an open handle would be
reported due to setTimeout promise not triggering
before the tests execution finishes.
To avoid open handles close the timeout instead of
setting a boolean variable and checking its value
after 5 (by default) seconds.

lib/conditional.module.ts

@@ -13,14 +13,11 @@ export class ConditionalModule {
     condition: string | ((env: NodeJS.ProcessEnv) => boolean),
     options?: { timeout: number },
   ) {
-    let configResolved = false;
     const { timeout = 5000 } = options ?? {};
-    setTimeout(() => {
-      if (!configResolved) {
-        throw new Error(
-          `Nest was not able to resolve the config variables within ${timeout} milliseconds. Bause of this, the ConditionalModule was not able to determine if ${module.toString()} should be registered or not`,
-        );
-      }
+    const timer = setTimeout(() => {
+      throw new Error(
+        `Nest was not able to resolve the config variables within ${timeout} milliseconds. Bause of this, the ConditionalModule was not able to determine if ${module.toString()} should be registered or not`,
+      );
     }, timeout);
     const returnModule: Required<
       Pick<DynamicModule, 'module' | 'imports' | 'exports'>
@@ -32,7 +29,7 @@ export class ConditionalModule {
       };
     }
     await ConfigModule.envVariablesLoaded;
-    configResolved = true;
+    clearTimeout(timer);
     const evaluation = condition(process.env);
     if (evaluation) {
       returnModule.imports.push(module);