fix(Select): shift+arrow will select multiple

[shani-terminus]

Also cleaned up the imports by removing the ones we aren't using.

ISSUES CLOSED: #1227

[codecov]

Codecov Report

Merging #1413 into master will increase coverage by 0.05%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #1413      +/-   ##
==========================================
+ Coverage   99.38%   99.43%   +0.05%     
==========================================
  Files         101      101              
  Lines        3747     3748       +1     
  Branches      555      555              
==========================================
+ Hits         3724     3727       +3     
+ Misses         23       21       -2

Impacted Files	Coverage Δ
terminus-ui/select/src/select.component.ts	97.09% <100%> (+0.36%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update ea7273c...6ba56fd. Read the comment docs.

[codecov]

Codecov Report

Merging #1413 into master will increase coverage by 0.05%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #1413      +/-   ##
==========================================
+ Coverage   99.38%   99.43%   +0.05%     
==========================================
  Files         101      101              
  Lines        3747     3748       +1     
  Branches      555      554       -1     
==========================================
+ Hits         3724     3727       +3     
+ Misses         23       21       -2

Impacted Files	Coverage Δ
terminus-ui/select/src/select.component.ts	97.09% <100%> (+0.36%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update ea7273c...ce53da1. Read the comment docs.