[JIRAALIGN-1701] Grammar error on People page

Problem encountered

Grammar error on "People" page in Jira Align administration. Error is in the message that appears when no users appear in list.

• BASE_URL/MasterUserList
• Search for a user that does not exist - This will make the following text visible:

  • Either there aren't any Users in your current configuration or you don't have any defined.
    Create an User here

The text that appears has a grammatical error.

Incorrect:

Create an User here

Correct:

Create a User here

Reference: https://owl.purdue.edu/owl/general_writing/grammar/articles_a_versus_an.html

Suggested change:

Fix grammatical error. Consider improving entire message while correcting the error.

• "you don't have any defined" does not make sense considering there must be at least one user (the admin who is viewing the page)
• May be nice to add info (or link to info) telling user how to reset configuration and/or clear filters so that all users show