Tighten Auth & Email route rate limits

[hardillb]

fixes FlowFuse/security#60

Description

Related Issue(s)

FlowFuse/security#60

Checklist

• I have read the contribution guidelines
• Suitable unit/system level tests have been added and they pass
• Documentation has been updated
  • Upgrade instructions
  • Configuration details
  • Concepts
• Changes flowforge.yml?
  • Issue/PR raised on FlowFuse/helm to update ConfigMap Template
  • Issue/PR raised on FlowFuse/CloudProject to update values for Staging/Production

Labels

• Backport needed? -> add the backport label
• Includes a DB migration? -> add the area:migration label

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (463a348) 40.98% compared to head (7c1fc10) 41.03%.
Report is 7 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3326      +/-   ##
==========================================
+ Coverage   40.98%   41.03%   +0.04%     
==========================================
  Files         605      605              
  Lines       22731    22733       +2     
  Branches     5473     5485      +12     
==========================================
+ Hits         9317     9328      +11     
+ Misses      13414    13405       -9     

Flag	Coverage Δ
backend	77.77% <100.00%> (+0.08%)	⬆️
frontend	2.05% <0.00%> (-0.01%)	⬇️

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