Allow subteams to inherit custom emoji set

Hello,

I uploaded my emojis to main team, the subteams I create do not get access to these however, is that intentional or is it possible to extend the custom emoji set to subteams?

No file, test, or entry point is named. Start by tracing how custom emoji access is determined for a main team and its subteams, then confirm the expected inheritance behavior with maintainers. Done means subteams can access the parent team's custom emoji set without breaking existing team boundaries.

Written by the indexing model from the issue text.