[Cashtab] removed extra spaces on currency ticker

Summary: Removed extra space after currency ticker on 'not enough XEC to mint token' error text. Related to task T2056.

Test Plan:
cd web/cashtab && npm start
navigate to settings tab
select empty wallet
navigate to eTokens page
ensure extra space is removed from error text

Reviewers: bytesofman, #bitcoin_abc

Reviewed By: bytesofman, #bitcoin_abc

Subscribers: emack

Differential Revision: https://reviews.bitcoinabc.org/D10640