Problem Statement/Rationale

Compass overwrites the appName field in connection string even when explicitly specified.

Steps to Reproduce

• Open Compass
• Connect to an instance with a connection string (doesn't need to specify) with or without an appname field
• Disconnect to check the settings that were actually used
• Note "&appname=MongoDB%20Compass" appears in the connection string, even if that field was specified with another value

Expected Results

I expect appname to keep its explicitly set value.

Actual Results

The appname field is added when omited, or overwritten with a value of "MongoDB%20Compass"

Additional Notes

Issue seems to come from https://github.com/mongodb-js/compass/blob/fe5fc2925a2621b2a69c9dc835de68da1a393be5/packages/compass/src/app/migrations/legacy-connection.js#L686

I suggest either removing these lines, or using the default value only if it wasn't specified explicitly in the connection string.