PyAPI: remove use of BaseException

BaseException was used as a catch-all in situations where it
didn't make sense and where "Exception" is more appropriate
based on Python's documentation & error checking tools,
`pylint` warns `broad-exception-caught` for e.g.

BaseException includes SystemExit, KeyboardInterrupt & GeneratorExit,
so unless the intention is to catch calls to `sys.exit(..)`,
breaking a out of a loop using Ctrl-C or generator-exit,
then it shouldn't be used.

Even then, it's preferable to catch those exceptions explicitly.

tests/python/bl_pyapi_bpy_driver_secure_eval.py

@@ -92,7 +92,7 @@ class _TestExprMixIn:
             )
             # exec(expr_code, {}, bpy.app.driver_namespace)
             ex = None
-        except BaseException as ex_test:
+        except Exception as ex_test:
             ex = ex_test
 
         if self.expressions_expect_unreachable: