remove incorrect apphosting:backends:create log that indicates branch does not exist when it does (#8385)

Author: mathu97

src/apphosting/githubConnections.ts

@@ -471,9 +471,6 @@ export async function promptGitHubBranch(repoLink: devConnect.GitRepositoryLink)
     },
   });
 
-  utils.logWarning(
-    `The branch "${branch}" does not exist on "${extractRepoSlugFromUri(repoLink.cloneUri) ?? ""}". Please enter a valid branch for this repo.`,
-  );
   return branch;
 }