Updated admin mentorship dashboard

[hannahstorer]

Updates:

• Renamed "View Pairs" quick action button to "View Matches"
• Fixed the welcome header rank display to show just the title ("Sergeant" instead of "e5-sergeant")
• Made all stat cards a consistent fixed height so titles and numbers are lined up
• Renamed the statistics section to "GuardConnect Mentorship Growth Statistics"
• Reduced the statistics to 3 cards (Total Mentorship Users, Mentorship Users Active Now, and Number of Mentees Waiting for Matching)
• Combined the growth stats and chart into one "GuardConnect Mentorship Growth Statistics" section
• Added a 30/90/180 day filter that updates growth data from the backend
• Moved Active Mentorship Pairs into the growth section and changed it so it's filtered by the time period
• Added a Download PDF button that creates a pdf download of the statistics for the time period
• Formatted growth cards so the time period is underneath the card title

[linear]

GC-67 Update mentorship admin page

[filic2005]

LGTM