[web] Introduce calculateTooltipSize util function

Summary:
Introduce calculation of tooltip size basing on labels size and number of actions inside.
Some parts of this logic was in findTooltipPosition before

Test Plan: Flow; Tested with the rest of diffs stack.

Reviewers: tomek, atul, abosh

Reviewed By: tomek

Subscribers: ashoat

Differential Revision: https://phab.comm.dev/D4914