Allow there to be no Django apps. (#22005)

The code clearly intended this, due to the early
return check, but the glob did not admit a non-match.

docs/notes/2.26.x.md

@@ -82,6 +82,8 @@ The Pants repo now uses Ruff format in lieu of Black. This was not a drop-in rep
 
 `@rule` decorators have been re-typed, which should allow better call site return-type visibility (fewer `Unknown`s and `Any`s). Decorator factories of the form `@rule(desc=..., level=..., ...)` have also been strongly typed. This may cause typechecking errors for plugin authors, if the plugin is using incorrect types. However, this likely would have manifested as a runtime crash, otherwise.
 
+A bug in the Django backend has been fixed so that a repo may have no Django apps without error. 
+
 [Pytype](https://www.pantsbuild.org/stable/reference/subsystems/pytype) was updated to version 2024.9.13 - which is the [last to support Python 3.8 and Python 3.9](https://github.com/google/pytype/blob/main/CHANGELOG).
 
 #### Shell

src/python/pants/backend/python/framework/django/detect_apps.py

@@ -11,6 +11,7 @@
 from pants.backend.python.target_types import InterpreterConstraintsField
 from pants.backend.python.util_rules.interpreter_constraints import InterpreterConstraints
 from pants.backend.python.util_rules.pex_environment import PythonExecutable
+from pants.base.glob_match_error_behavior import GlobMatchErrorBehavior
 from pants.base.specs import FileGlobSpec, RawSpecs
 from pants.engine.fs import AddPrefix, CreateDigest, Digest, FileContent, MergeDigests
 from pants.engine.internals.selectors import Get, MultiGet
@@ -88,7 +89,9 @@ async def detect_django_apps(python_setup: PythonSetup) -> DjangoApps:
         Targets,
         RawSpecs,
         RawSpecs.create(
-            specs=[FileGlobSpec("**/apps.py")], description_of_origin="Django app detection"
+            specs=[FileGlobSpec("**/apps.py")],
+            description_of_origin="Django app detection",
+            unmatched_glob_behavior=GlobMatchErrorBehavior.ignore,
         ),
     )
     if not targets: