Remove strategic bombing land unit limitation

[ron-murhammer]

Allow land units to perform strategic bombing. I did some basic testing and it seems to work fine. Just appears to be a unnecessary parsing check.

[codecov-io]

Codecov Report

Merging #4804 into master will decrease coverage by <.01%.
The diff coverage is 0%.

@@             Coverage Diff              @@
##             master    #4804      +/-   ##
============================================
- Coverage     23.21%   23.21%   -0.01%     
  Complexity     6150     6150              
============================================
  Files           860      860              
  Lines         69743    69743              
  Branches      11168    11168              
============================================
- Hits          16190    16189       -1     
  Misses        51528    51528              
- Partials       2025     2026       +1

Impacted Files	Coverage Δ	Complexity Δ
...s/strategy/triplea/attachments/UnitAttachment.java	43.33% <0%> (ø)	254 <0> (ø)	⬇️
...java/games/strategy/triplea/delegate/DiceRoll.java	64.42% <0%> (-0.32%)	139% <0%> (-1%)
.../src/main/java/games/strategy/net/nio/Decoder.java	66.07% <0%> (+1.78%)	12% <0%> (+1%)	⬆️

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