Fixes content offset adjustment

[diegosanchezr]

Fixes bug:

1. Open a conversation with few messages
2. Open the keyboard

AR: distance to keyboard is preserved, there's a gap between latest message and the keyboard
ER: latest message appears just above the keyboard

[codecov-io]

Current coverage is 64.42%

Merging #110 into dev will increase coverage by +0.08% as of 928e1ba

@@              dev    #110   diff @@
=====================================
  Files          59      59       
  Stmts        3096    3103     +7
  Branches        0       0       
  Methods         0       0       
=====================================
+ Hit          1992    1999     +7
  Partial         0       0       
  Missed       1104    1104       

Review entire Coverage Diff as of 928e1ba

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