[Cashtab] Patch edit svg size FF

Summary: Related to T2641. Edit wallet name icon not scaling properly in firefox, addressed in this diff.

Test Plan:
cd web/cashtab && npm start
navigate to localhost:3000 in firefox
observe that the edit wallet name icon in the wallet label component is the appropriate size.

Reviewers: bytesofman, #bitcoin_abc

Reviewed By: bytesofman, #bitcoin_abc

Differential Revision: https://reviews.bitcoinabc.org/D11910