[Send v2][Enhancement] Password preview should be added to the "Protect with password" field

[Softvision-RemusDranca]

[Affected versions]:

• Firefox 63.0.3 and above

[Affected Platforms]:

• All Windows
• All Mac
• All Linux

[Prerequisites]:

• Have a new Firefox profile created.
• Have a file created for upload.

[Steps to reproduce]:

1. Open the new Firefox profile and navigate to "https://vnext.send.nonprod.cloudops.mozgcp.net/" page.
2. Drag and drop the file from prerequisites.
3. Click the "Protect with password" option and enter a password.
4. Observe the "Protect with password" section.

[Expected result]:

• A password preview should be displayed.

[Actual result]:

• No password preview is displayed.

[Notes]:

• Attached is a screen recording of the issue:
  

[johngruen]

@youwenliang can we get a mockup for this?

[dennis-mb]

Alternatively or additionally, employ a second "reenter password" field in order to prevent that typos in the password render the upload useless.