feat(authentication): configurable magicLink dispatch URI, magic token consumption endpoint

[kon14]

This PR introduces a configurable magic link dispatch URI config option for customizing magic token consumption.
When provided, magic token emails will link to the specified address, instead of the default magic token hook endpoint.

I've also introduced some str nullity check fixes as well as workarounds for trailing slashes.

This PR also modifies internal redirectUri behavior.
These are no longer appended to the magic link as query params and are retrieved from the token doc instead.
Non-overriden redirectUri values are intentionally not stored in token.data and coalesced back into latest config values during token retrieval (in hook endpoint).

What kind of change does this PR introduce?

• Bugfix
• Feature
• Code style update
• Refactor
• Build-related changes
• Other (please describe)

Does this PR introduce a breaking change?

• Yes
• No

The PR fulfills these requirements:

• It's submitted to the main branch
• When resolving a specific issue, it's referenced in the PR's description (e.g. fix #xxx, where "xxx" is the issue number)

If adding a new feature, the PR's description includes:

• A convincing reason for adding this feature

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