syn2mas requires PostgreSQL password

[xanderio]

Describe the bug
A clear and concise description of what the bug is.

When trying to migrate my synapse installation to MAS I've noticed that syn2mas is unable to handle connecting to a postgres database without a password being set in the config. This is that case as my synapse installation uses postgres peer authentication via a unix domain socket.

This somewhat unhelpful error is printed to the console.

[2025-01-04T14:30:06.477] [ERROR] default - Error: SASL: SCRAM-SERVER-FIRST-MESSAGE: client password must be a string
    at Object.continueSession (/nix/store/yapm7qri4f4rmgjima6spz90pzd4lb85-syn2mas-0.12.0/lib/node_modules/@vector-im/syn2mas/node_modules/pg/lib/crypto/sasl.js:24:11)
    at Client._handleAuthSASLContinue (/nix/store/yapm7qri4f4rmgjima6spz90pzd4lb85-syn2mas-0.12.0/lib/node_modules/@vector-im/syn2mas/node_modules/pg/lib/client.js:272:18)
    at Connection.emit (node:events:518:28)
    at /nix/store/yapm7qri4f4rmgjima6spz90pzd4lb85-syn2mas-0.12.0/lib/node_modules/@vector-im/syn2mas/node_modules/pg/lib/connection.js:117:12
    at Parser.parse (/nix/store/yapm7qri4f4rmgjima6spz90pzd4lb85-syn2mas-0.12.0/lib/node_modules/@vector-im/syn2mas/node_modules/pg-protocol/dist/parser.js:36:17)
    at Socket.<anonymous> (/nix/store/yapm7qri4f4rmgjima6spz90pzd4lb85-syn2mas-0.12.0/lib/node_modules/@vector-im/syn2mas/node_modules/pg-protocol/dist/index.js:11:42)
    at Socket.emit (node:events:518:28)
    at addChunk (node:internal/streams/readable:561:12)
    at readableAddChunkPushByteMode (node:internal/streams/readable:512:3)
    at Readable.push (node:internal/streams/readable:392:5)

To Reproduce
Steps to reproduce the behavior:

1. Create homeserver.yaml containg

database:
  args:
    database: matrix-synapse
    user: matrix-synapse
  name: psycopg2

2. sudo -u matrix-synapse syn2mas --command=advisor --synapseConfigFile=homeserver.yaml
3. See error

Expected behavior
syn2mas being able to connect to a postgres without the need for a password.