Invalidate layout when view is transitioning sizes

[esilverberg]

Fix issue where cells are not drawn properly when rotating from portrait to landscape

This addresses issue https://github.com/badoo/Chatto/issues/712

[codecov-commenter]

Codecov Report

Merging #713 (3df9bdd) into master (322933d) will decrease coverage by 0.01%. The diff coverage is 0.00%.

@@            Coverage Diff             @@
##           master     #713      +/-   ##
==========================================
- Coverage   59.07%   59.06%   -0.02%     
==========================================
  Files         101      101              
  Lines        5229     5230       +1     
==========================================
  Hits         3089     3089              
- Misses       2140     2141       +1     

Impacted Files	Coverage Δ
...Source/ChatController/BaseChatViewController.swift	69.88% <0.00%> (-0.21%)	:arrow_down:

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