Magic Links: Limit the code input text field on login to 6 chars

[charliescheer]

Fix

We recently implemented code authentication into Simplenote. One thing we were concerned about is what would happen if someone put in a huge amount of characters into the code field input. Nothing should happen, but it seemed like a good idea to limit the character count to on the code input text field.

So in this PR I have done just that

Test

(Required) List the steps to test the behavior. For example:

1. Fresh install Simplenote. Go to login and enter your email
2. when the code input appears, attempt to put in more characters than the code limit of 6

• Confirm you can only put 6 characters in the code field
• Confirm that the username and password fields do not have a limit in them

Review

(Required) Add instructions for reviewers. For example:

Only one developer is required to review these changes, but anyone can perform the review.

Release

(Required) Add a concise statement to RELEASE-NOTES.txt if the changes should be included in release notes. Include details about updating the notes in this section. For example:

These changes do not require release notes.

[jleandroperez]