More specific type annotation for BaseJobExec.parse_status()

Add type annotation to ``BaseJobExec.parse_single_status()``

Follow-up on galaxyproject#17367 (comment) .

Needed to add ``TypeAlias`` to ``model.Job.states`` to fix:

```
lib/galaxy/jobs/runners/util/cli/job/__init__.py:67: error: Variable "galaxy.jobs.runners.util.cli.job.job_states" is not valid as a type  [valid-type]
        def parse_status(self, status: str, job_ids: List[str]) -> Dict[str, job_states]:
                                                                             ^
```

See https://mypy.readthedocs.io/en/stable/common_issues.html#variables-vs-type-aliases :

> You should always use ``TypeAlias`` to define a type alias in a class body
> or inside a function.

lib/galaxy/jobs/runners/util/cli/job/__init__.py

@@ -64,13 +64,13 @@ def get_single_status(self, job_id):
         """
 
     @abstractmethod
-    def parse_status(self, status: str, job_ids: List[str]) -> Dict[str, str]:
+    def parse_status(self, status: str, job_ids: List[str]) -> Dict[str, job_states]:
         """
         Parse the statuses of output from get_status command.
         """
 
     @abstractmethod
-    def parse_single_status(self, status, job_id):
+    def parse_single_status(self, status: str, job_id: str) -> job_states:
         """
         Parse the status of output from get_single_status command.
         """

lib/galaxy/jobs/runners/util/cli/job/torque.py

@@ -100,7 +100,7 @@ def parse_single_status(self, status, job_id):
         # no state found, job has exited
         return job_states.OK
 
-    def _get_job_state(self, state: str) -> str:
+    def _get_job_state(self, state: str) -> job_states:
         try:
             return {"E": job_states.RUNNING, "R": job_states.RUNNING, "Q": job_states.QUEUED, "C": job_states.OK}[state]
         except KeyError:

lib/galaxy/model/__init__.py

@@ -33,6 +33,7 @@
     Tuple,
     Type,
     TYPE_CHECKING,
+    TypeAlias,
     Union,
 )
 from uuid import (
@@ -1380,7 +1381,7 @@ class Job(Base, JobLike, UsesCreateAndUpdateTime, Dictifiable, Serializable):
     _numeric_metric = JobMetricNumeric
     _text_metric = JobMetricText
 
-    states = JobState
+    states: TypeAlias = JobState
 
     # states that are not expected to change, except through admin action or re-scheduling
     terminal_states = [states.OK, states.ERROR, states.DELETED]