Remove redundant logs

[djshow832]

Development Task

There are some redundant logs, such as:

[2023/02/09 08:39:20.086 +00:00] [INFO] [main.proxy.conn.be.authenticator] [backend/authenticator.go:196] [backend does not support capabilities from proxy] [connID=0] [remoteAddr=10.244.0.197:46650] [common=CLIENT_LONG_PASSWORD|CLIENT_FOUND_ROWS|CLIENT_LONG_FLAG|CLIENT_CONNECT_WITH_DB|CLIENT_LOCAL_FILES|CLIENT_PROTOCOL_41|CLIENT_INTERACTIVE|CLIENT_SSL|CLIENT_TRANSACTIONS|CLIENT_SECURE_CONNECTION|CLIENT_MULTI_STATEMENTS|CLIENT_MULTI_RESULTS|CLIENT_PLUGIN_AUTH|CLIENT_CONNECT_ATTS|CLIENT_DEPRECATE_EOF] [proxy=CLIENT_ODBC|CLIENT_RESERVED|CLIENT_PLUGIN_AUTH_LENENC_CLIENT_DATA] [backend=]

[2023/02/09 08:54:19.641 +00:00] [WARN] [main.proxy.conn.be] [backend/backend_conn_mgr.go:494] [redirect connection failed] [connID=241] [remoteAddr=10.244.0.197:47898] [from=tc-tidb-1.tc-tidb-peer.testbed-endless-tiproxy-zc9wr.svc:4000] [to=tc-tidb-0.tc-tidb-peer.testbed-endless-tiproxy-zc9wr.svc:4000] [redirect_err="failed to read the connection: EOF"] [redirect_errVerbose="failed to read the connection: EOF\ngithub.com/pingcap/TiProxy/pkg/proxy/net.(*PacketIO).wrapErr\n\t/proxy/pkg/proxy/net/packetio.go:111\ngithub.com/pingcap/TiProxy/pkg/proxy/net.(*PacketIO).ReadPacket\n\t/proxy/pkg/proxy/net/packetio.go:195\ngithub.com/pingcap/TiProxy/pkg/proxy/backend.(*CmdProcessor).query\n\t/proxy/pkg/proxy/backend/cmd_processor_query.go:42\ngithub.com/pingcap/TiProxy/pkg/proxy/backend.(*BackendConnManager).querySessionStates\n\t/proxy/pkg/proxy/backend/backend_conn_mgr.go:344\ngithub.com/pingcap/TiProxy/pkg/proxy/backend.(*BackendConnManager).tryRedirect\n\t/proxy/pkg/proxy/backend/backend_conn_mgr.go:409\ngithub.com/pingcap/TiProxy/pkg/proxy/backend.(*BackendConnManager).processSignals\n\t/proxy/pkg/proxy/backend/backend_conn_mgr.go:368\ngithub.com/pingcap/TiProxy/pkg/proxy/backend.(*BackendConnManager).Connect.func1\n\t/proxy/pkg/proxy/backend/backend_conn_mgr.go:179\ngithub.com/pingcap/TiProxy/lib/util/waitgroup.(*WaitGroup).Run.func1\n\t/proxy/lib/util/waitgroup/waitgroup.go:33\nruntime.goexit\n\t/usr/lib/go/src/runtime/asm_amd64.s:1594"]

[2023/02/09 08:54:19.562 +00:00] [INFO] [main.proxy.conn] [client/client_conn.go:83] [] [connID=351] [remoteAddr=10.244.0.197:53424] [proxy-protocol=false] [clientErr=false] [serverErr=true]
[2023/02/09 08:54:19.562 +00:00] [INFO] [main.proxy] [proxy/proxy.go:170] [connection closed] [connID=351] [remoteAddr=10.244.0.197:53424]

[xhebox]

@djshow832 The first one are sometime useful, maybe we can mark them as debug.