feat(sticker): add a direct link to room/space settings when sticker list is empty

[ellieplayswow]

Description

hey! i was helping onboard some friends and sable is really cool. i wanted to add a bit of an easier way to get into the sticker page, so i added quick links to them in the room & space bits of text:

there doesn't seem to be an existing style to piggy-back off for the links, so i put something quick together. happy to change to whatever works best, the contrast is probably a bit low in the default dark theme?

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings

AI disclosure:

• Partially AI assisted (clarify which code was AI assisted and briefly explain what it does).
• Fully AI generated (explain what all the generated code does in moderate detail).