Permission graph does not support schemas with slashes

[alxnddr]

Describe the bug
Schemas like special_/_#_%_'__._&_>_:_ _end can't be added to the permissions graph because they got trimmed:

Metadata request contains the correct schema name starting with special_/

Permissions graph returns a trimmed name

To Reproduce
Steps to reproduce the behavior:

1. Connect a database with a schema called special_/_#_%_'__._&_>_:_ _end
2. Go to the permissions page and try setting data permissions for the schema

Expected behavior
Permissions graph contains full schema names

Information about your Metabase Installation:
Latest master

[qnkhuat]

I'm fixing this in #22090

But I also found a bug in FE when I change Permissions Data Access Permission to Granular of a scheme with special characters, FE it'll fail because the schema name is not encoded.

Reproduce:

1. Connect a database with a schema called special_/_#_%_'__._&_>_:_ _end
2. Go to Admin -> Permissions -> Data
3. Change Permissions of schema special_/_#_%_'__._&_>_:_ _end to Granular

22047.mov

[qnkhuat]

Reopen since we still have a bug in FE

[flamber]

@alxnddr I think you can quickly fix this, since its likely very similar to the other FE fixes you did.