fix(mail-merge): Remove unecessary shouldComponentUpdate on decorator
fix(mail-merge): Remove unecessary shouldComponentUpdate on decorator

- `shouldComponentUpdate` on ListensToMailMergeSession decorator prevented
the default TokenizingTexField from being rendered even when mail merge
was inactive.
- It incorrectly assumed that the only state the decorated component
cares about was the mail merge session state

simonft/nylas-mail,nylas/nylas-mail,simonft/nylas-mail,nirmit/nylas-mail,nylas-mail-lives/nylas-mail,nirmit/nylas-mail,nylas/nylas-mail,simonft/nylas-mail,simonft/nylas-mail,nylas/nylas-mail,simonft/nylas-mail,nylas-mail-lives/nylas-mail,nirmit/nylas-mail,nylas-mail-lives/nylas-mail,nylas-mail-lives/nylas-mail,nylas/nylas-mail,nylas-mail-lives/nylas-mail,nirmit/nylas-mail,nirmit/nylas-mail,nylas/nylas-mail