MSSQL connector fails to connect to a Named Instance

## Environment
- **Airbyte version**: 0.40.32
- **OS Version / Instance**: Windows 11
- **Deployment**: Docker
- **Source Connector and version**: [airbyte/source-mssql](https://docs.airbyte.com/integrations/sources/mssql), 0.4.28
- **Destination Connector and version**: NONE
- **Step where error happened**: Setup new connection

## Current Behavior
When I try to connect to an external (aka, non docker database), I expect that, if the database instance is not the default, it should connect if I specify the instance name, by separating host name / instance name with '\' or '\\' (if escaping is needed).

## Expected Behavior
Airbyte fails to connect.

## Logs
Airbyte fails to download the server logs so I can only provide the logs shown in the New source UI.

Logs
2023-02-03 10:17:05 INFO i.a.w.i.VersionedAirbyteStreamFactory(create):107 - Reading messages from protocol version 0.2.0, messages will be upgraded to protocol version 1.0.0
2023-02-03 10:17:08 INFO i.a.w.i.DefaultAirbyteStreamFactory(internalLog):167 - starting source: class io.airbyte.integrations.source.mssql.MssqlSource
2023-02-03 10:17:08 INFO i.a.w.i.DefaultAirbyteStreamFactory(internalLog):167 - integration args: {check=null, config=source_config.json}
2023-02-03 10:17:08 INFO i.a.w.i.DefaultAirbyteStreamFactory(internalLog):167 - Running integration: io.airbyte.integrations.base.ssh.SshWrappedSource
2023-02-03 10:17:08 INFO i.a.w.i.DefaultAirbyteStreamFactory(internalLog):167 - Command: CHECK
2023-02-03 10:17:08 INFO i.a.w.i.DefaultAirbyteStreamFactory(internalLog):167 - Integration config: IntegrationConfig{command=CHECK, configPath='source_config.json', catalogPath='null', statePath='null'}
2023-02-03 10:17:08 WARN i.a.w.i.DefaultAirbyteStreamFactory(internalLog):164 - Unknown keyword order - you should define your own Meta Schema. If the keyword is irrelevant for validation, just use a NonValidationKeyword
2023-02-03 10:17:08 WARN i.a.w.i.DefaultAirbyteStreamFactory(internalLog):164 - Unknown keyword airbyte_secret - you should define your own Meta Schema. If the keyword is irrelevant for validation, just use a NonValidationKeyword
2023-02-03 10:17:08 INFO i.a.w.i.DefaultAirbyteStreamFactory(internalLog):167 - Starting connection with method: NO_TUNNEL
2023-02-03 10:17:08 INFO i.a.w.i.DefaultAirbyteStreamFactory(internalLog):167 - HikariPool-1 - Starting...
2023-02-03 10:17:09 INFO i.a.w.i.DefaultAirbyteStreamFactory(internalLog):167 - HikariPool-1 - Start completed.
2023-02-03 10:18:09 INFO i.a.w.i.DefaultAirbyteStreamFactory(internalLog):167 - HikariPool-1 - Shutdown initiated...
2023-02-03 10:19:08 INFO i.a.w.i.DefaultAirbyteStreamFactory(internalLog):167 - HikariPool-1 - Shutdown completed.
2023-02-03 10:19:08 INFO i.a.w.i.DefaultAirbyteStreamFactory(internalLog):167 - Completed integration: io.airbyte.integrations.base.ssh.SshWrappedSource
2023-02-03 10:19:08 INFO i.a.w.i.DefaultAirbyteStreamFactory(internalLog):167 - completed source: class io.airbyte.integrations.source.mssql.MssqlSource
2023-02-03 10:19:08 INFO i.a.w.g.DefaultCheckConnectionWorker(run):114 - Check connection job received output: io.airbyte.config.StandardCheckConnectionOutput@29f68141[status=failed,message=State code: 08S01; Message: The TCP/IP connection to the host 172.16.0.21, port 1433 has failed. Error: "Connection refused. Verify the connection properties. Make sure that an instance of SQL Server is running on the host and accepting TCP/IP connections at the port. Make sure that TCP connections to the port are not blocked by a firewall.".]
2023-02-03 10:19:08 INFO i.a.w.t.TemporalAttemptExecution(get):163 - Stopping cancellation check scheduling...
2023-02-03 10:19:08 INFO i.a.c.i.LineGobbler(voidCall):114 -
2023-02-03 10:19:08 INFO i.a.c.i.LineGobbler(voidCall):114 - ----- END CHECK -----
2023-02-03 10:19:08 INFO i.a.c.i.LineGobbler(voidCall):114 -

[scheduler-logs.txt](https://github.com/airbytehq/airbyte/files/10577992/scheduler-logs.txt)

## Steps to Reproduce
1. Try to setup a new source connection
2. Compile the required fields
3. In the 'Host' field, insert the address and specify an instance name (eg. 127.0.0.1\\sql2019)

## Are you willing to submit a PR?
I can try but I'm not sure I'll complete it in a short time.