2026.5.x Rust-based Worker Breaks Multi-host Postgres Support

### Describe the bug

In previous versions, the Python-based worker supports multi-host Postgres HA natively via libpq's support for multiple DB nodes. It can be achieved by specifying the environment variable `AUTHENTIK_POSTGRESQL__HOST=host1,host2`

However, the new Rust-worker does not support this syntax, settings like above will simply result in Name not resolved error.

The `sqlx` library used by Rust worker does not support multi-host syntax as of writing https://github.com/transact-rs/sqlx/issues/2290.

### How to reproduce

1. Specify `AUTHENTIK_POSTGRESQL__HOST=host1,host2` (Or any two hosts separated by a comma)
2. Start the worker

### Expected behavior

Multi-host failover support similar to previous version of Worker.

### Screenshots

_No response_

### Additional context

_No response_

### Deployment Method

Docker

### Version

2026.5.x

### Relevant log output

```shell

```