fix: handle @ in display name when using MailHelper.StringToEmailAddress

[Fieora]

fix email regex to allow email addresses in the display name.

Input: [email protected] <[email protected]>
Expected:
-NameGroup: [email protected]
-EmailGroup: [email protected]

Initial:
-NameGroup: {empty string}
-EmailGroup: [email protected] <[email protected]
Result: A match is found, therefore there is no error caught and email string is bad

After:
-NameGroup: [email protected]
-EmailGroup: [email protected]
Result: Success!

Other test cases:
-<[email protected]> SUCCESS
-[email protected] SUCCESS
-username <[email protected]> SUCCESS
-username <usernameexample.com> NO MATCH (SUCCESS)

Testing with the updated regular expression can be done here

Fixes

Fixes #902

Checklist

• I acknowledge that all my contributions will be made under the project's license
• I have made a material change to the repo (functionality, testing, spelling, grammar)
• I have read the [Contribution Guide] and my PR follows them.
• I updated my branch with the development branch.
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation about the functionality in the appropriate .md file
• I have added in line documentation to the code I modified

Short description of what this PR does:

• Flips the or (|) clause order in the regular expression.

If you have questions, please send an email to Twilio Sendgrid, or file a Github Issue in this repository.

[Fieora]

Hey, this is my first pull request on a major project!

I was able to run the tests, however I didn't add any new tests or comments as this is a one line change.
I am also not very experienced with regex or tests, so I could have easily missed something.

[Fieora]

I have added test cases for MailHelper.StringToEmailAddress()

[aevitas]

Hey @Fieora, great job on the PR! I think your changes look good, except for one minor details, and that's the casing of parameters. In C#, it's custom to use camelCase for method parameters. It'd be great if you could fix them, but otherwise good work! :)

[childish-sambino]

LGTM