Bug: Do not inform if email exists in system when resetting password

[i-oden]

Before submitting this PR

1. Description: When a user tries to reset the password, the DDS currently displays a different message depending on if the email is registered to a user or not. This means that someone could potentially guess emails during an attempt to hack the system. The message should be identical, which this PR changes.
2. Jira task / GitHub issue: DDS-1508
3. How to test:
   1. Start up dds_web locally (docker)
   2. Go to 127.0.0.1:5000 -- the DDS web interface
   3. Click reset password
   4. Fill in email addresses -- the message should be the same, but the email may or may not be sent.
      1. An email address that's not registered
      2. An email address that is registered
      3. An email address that is registered but the user is deactivated - This will still currently display a different message, but it's rare enough (or possibly not used at all at the moment) that it's worth spending time on at the moment.
4. Type of change: Check the relevant boxes in the section below
5. Add docstrings and comments to code, even if you personally think it's obvious.

What type of change(s) does the PR contain?

• New feature
  • Breaking: Please describe the reason for the break and how we can fix it.
  • Non-breaking
• Database change
  • Migration included in PR
  • Migration not needed
• Bug fix
  • Breaking: Please describe the reason for the break and how we can fix it.
  • Non-breaking
• Security Alert fix
• Documentation
• Tests (only)
• Workflow

Checklist

• Sprintlog
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• Rebase / Update / Merge from base branch (the branch from which the current is forked)
  • Done
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• Blocking PRs
  • Merged
  • No blocking PRs
• PR to master branch
  • Yes: Read the release instructions
    • I have followed steps 1-7.
  • No

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• Snyk: Security scanner
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  • Alerts fixed: What?
  • Alerts ignored / dismissed: Why?
  • Passed

[valyo]

Works as intended