fix(datepicker): if min date is last day of a month

[valorkin]

user should be able to navigate into that month

fixes #3102

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• built and tested the changes locally.
• added/updated tests.
• added/updated API documentation.
• added/updated demos.

[codecov]

Codecov Report

Merging #3113 into development will decrease coverage by 1.49%.
The diff coverage is 0%.

@@              Coverage Diff               @@
##           development    #3113     +/-   ##
==============================================
- Coverage        65.44%   63.94%   -1.5%     
==============================================
  Files              209      209             
  Lines             5617     5617             
  Branches           988      988             
==============================================
- Hits              3676     3592     -84     
  Misses            1678     1678             
- Partials           263      347     +84

Impacted Files	Coverage Δ
src/datepicker/engine/flag-days-calendar.ts	15.62% <ø> (ø)	⬆️
src/datepicker/utils/bs-calendar-utils.ts	34.78% <0%> (ø)	⬆️
src/component-loader/component-loader.factory.ts	66.66% <0%> (-33.34%)	⬇️
...themes/bs/bs-datepicker-day-decorator.directive.ts	80% <0%> (-20%)	⬇️
...icker/themes/bs/bs-days-calendar-view.component.ts	63.15% <0%> (-10.53%)	⬇️
src/tabs/ng-transclude.directive.ts	50% <0%> (-10%)	⬇️
src/tabs/tab.directive.ts	89.13% <0%> (-8.7%)	⬇️
...emes/bs/bs-datepicker-navigation-view.component.ts	83.33% <0%> (-8.34%)	⬇️
src/collapse/collapse.directive.ts	89.74% <0%> (-7.7%)	⬇️
src/rating/rating.component.ts	68.33% <0%> (-6.67%)	⬇️
... and 22 more

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