import pydantic objects from the `_pydantic_compat` module (#17667)

This PR changes `from pydantic import BaseModel` to `from
synapse._pydantic_compat import BaseModel` (as well as `constr`,
`conbytes`, `conint`, `confloat`).

It allows `check_pydantic_models.py` to mock those pydantic objects only
in the synapse module, and not interfere with pydantic objects in
external dependencies.

This should solve the CI problems for #17144, which breaks because
`check_pydantic_models.py` patches pydantic models from
[scim2-models](https://scim2-models.readthedocs.io/).

/cc @DMRobertson @gotmax23
fixes #17659 


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* [x] [Code
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1 files changed, 8 insertions, 8 deletions

diff --git a/synapse/config/workers.py b/synapse/config/workers.py

index b013ffa354..ab896be307 100644
--- a/synapse/config/workers.py
+++ b/synapse/config/workers.py
@@ -22,17 +22,17 @@
 
 import argparse
 import logging
-from typing import TYPE_CHECKING, Any, Dict, List, Optional, Union
+from typing import Any, Dict, List, Optional, Union
 
 import attr
 
-from synapse._pydantic_compat import HAS_PYDANTIC_V2
-
-if TYPE_CHECKING or HAS_PYDANTIC_V2:
-    from pydantic.v1 import BaseModel, Extra, StrictBool, StrictInt, StrictStr
-else:
-    from pydantic import BaseModel, Extra, StrictBool, StrictInt, StrictStr
-
+from synapse._pydantic_compat import (
+    BaseModel,
+    Extra,
+    StrictBool,
+    StrictInt,
+    StrictStr,
+)
 from synapse.config._base import (
     Config,
     ConfigError,