Add java_language_level to the default projectview file

Closes #23903.

PiperOrigin-RevId: 684004084
Change-Id: I8667ab91e9f7a6e2d95d22ccf76634f5711b22c3

scripts/ij.bazelproject

diff --git a/scripts/ij.bazelproject b/scripts/ij.bazelproject
index 4be76d6..e3f4af3 100644
--- a/scripts/ij.bazelproject
+++ b/scripts/ij.bazelproject
@@ -25,3 +25,5 @@
   # These tests cause the build to fail on macOS:
   # https://github.com/bazelbuild/bazel/issues/13636
   -//src/test/shell/bazel:all_tests
+
+java_language_level: 21