syn2mas will not procced / fail dry run when warnings are present (with no way to bypass)

**Describe the bug**

I tried to migrate my homeserver to MAS following [the process](https://docs.element.io/latest/element-server-suite-pro/migration/MAS/?h=syn2mas#step-1-setup-matrix-authentication-service-and-prepare-the-migration) but found that I had some warnings (harmless, overall):

```
===== Warnings =====
These potential issues should be considered before migrating from Synapse to MAS right now:

• Synapse database contains 71147 guests which will be migrated are not supported by MAS. See https://github.com/element-hq/matrix-authentication-service/issues/1445

• Synapse database contains 3 non-email 3PIDs (probably phone numbers), which will be migrated but are not supported by MAS.

Error from server (BadRequest): container "syn2mas-migrate" in pod "matrix-syn2mas-8gs5f" is waiting to start: PodInitializing
```

which causes MAS to exit with an [exitcode 11](https://github.com/element-hq/matrix-authentication-service/blob/main/crates/cli/src/commands/syn2mas.rs#L32C7-L32C31) which means the migration cannot proceed. I can't see an exposed way to override this.

**Expected behavior**

I'd like to be able to migrate in spite of the warnings.

**Additional context**

This is ESS `26.1.0`