Handle ecoystem "links" to obey passed account

[tobiasKaminsky]

Imagine
Files with Account A and B
Notes with B

• open Files with A

• open Notes

• click within Notes on "Files"
  --> Files with Account B should open

• add for Files receiving side

• add for Notes receiving side

• test with non existing account -> proper warning, keep current account

Android: nextcloud/android#16186