fix(@angular/build): avoid extra tick in SSR dev-server builds

In SSR applications, an unnecessary event loop tick during server startup could lead to an incorrect platform being initialized.

This change introduces an `ngJitMode` define, which is set to `false` during AOT builds. This allows for the JIT-specific code paths to not be followed, preventing the async operations that caused the extra tick. This ensures that the server platform is correctly and synchronously initialized.

(cherry picked from commit 7b0f697)

Author: alan-agius4

packages/angular/build/src/builders/dev-server/vite-server.ts

@@ -456,6 +456,7 @@ export async function* serveWithVite(
         browserOptions.loader as EsbuildLoaderOption | undefined,
         {
           ...browserOptions.define,
+          'ngJitMode': browserOptions.aot ? 'false' : 'true',
           'ngHmrMode': browserOptions.templateUpdates ? 'true' : 'false',
         },
         extensions?.middleware,