Regex in Email handler matches tokens in long strings.

Problem/Motivation

While setting up a email, i had the subject of the email set a multi token string. This resulted in using the default value. Sample String value:

[webform_submission:user] - [webform_submission:values:site:raw] - [webform_submission:values:issue_summary]

The mapping logic detected this string to match the site field despite expecting the raw value of the token replaced string.

Proposed resolution

Pin the regex to the start and end of the string.