Prevent duplicate logging setup when running multiple Synapse instances (#19067)

Be mindful that it's possible to run Synapse multiple times in the same
Python process. So we only need to do some part of the logging setup
once.

- We only need to setup the global log record factory and context filter
once
 - We only need to redirect Twisted logging once


### Background

As part of Element's plan to support a light form of vhosting (virtual
host) (multiple instances of Synapse in the same Python process), we're
currently diving into the details and implications of running multiple
instances of Synapse in the same Python process.

"Per-tenant logging" tracked internally by
https://github.com/element-hq/synapse-small-hosts/issues/48

synmark/suites/logging.py

@@ -33,7 +33,7 @@ from twisted.internet.protocol import ServerFactory
 from twisted.logger import LogBeginner, LogPublisher
 from twisted.protocols.basic import LineOnlyReceiver
 
-from synapse.config.logger import _setup_stdlib_logging
+from synapse.config.logger import _setup_stdlib_logging, one_time_logging_setup
 from synapse.logging import RemoteHandler
 from synapse.synapse_rust import reset_logging_config
 from synapse.types import ISynapseReactor
@@ -115,10 +115,10 @@ async def main(reactor: ISynapseReactor, loops: int) -> float:
     }
 
     logger = logging.getLogger("synapse")
+    one_time_logging_setup(logBeginner=beginner)
     _setup_stdlib_logging(
         hs_config,  # type: ignore[arg-type]
         None,
-        logBeginner=beginner,
     )
 
     # Force a new logging config without having to load it from a file.