fix: Change content-type of ICS export

[iamareebjamal]

No description provided.

[codecov]

Codecov Report

Merging #7468 (58459b6) into development (707f160) will not change coverage.
The diff coverage is 0.00%.

@@             Coverage Diff              @@
##           development    #7468   +/-   ##
============================================
  Coverage        65.41%   65.41%           
============================================
  Files              265      265           
  Lines            13244    13244           
============================================
  Hits              8663     8663           
  Misses            4581     4581           

Impacted Files	Coverage Δ
app/api/custom/calendars.py	50.00% <0.00%> (ø)

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