Allow newline in Extra Network activation text

[w-e-w]

Description

Allow newline in Extra Network activation text

currently it is possible possible for the user to input newline into the activation text by shift + enter or copy and paste
when the activation contains new line, it breakes the javascript

changes / fix

• use json.dumps for quote_js so special characters such as newline also properly escaped
• use 's' flag for re_extranet regex so that . it matches all characters
• • re_extranet will have a minor merge conflict with ExtraNetworks: Performance Updates and Improvements #15530

Checklist:

• I have read contributing wiki page
• I have performed a self-review of my own code
• My code follows the style guidelines
• My code passes tests