fix: check for closeable() before calling in spatialnavigation

[mister-ben]

Description

Passing the back key causes an error in spatial navigation if the event target does not have a closeable function.

Specific Changes proposed

Add a check before calling.

Requirements Checklist

• Feature implemented / Bug fixed
• If necessary, more likely in a feature request than a bug fix
  • Change has been verified in an actual browser (Chrome, Firefox, IE)
  • Unit Tests updated or fixed
  • Docs/guides updated
  • Example created (starter template on JSBin)
  • Has no DOM changes which impact accessiblilty or trigger warnings (e.g. Chrome issues tab)
  • Has no changes to JSDoc which cause npm run docs:api to error
• Reviewed by Two Core Contributors

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 83.18%. Comparing base (65f8546) to head (73dbd90).
Report is 7 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #8832   +/-   ##
=======================================
  Coverage   83.18%   83.18%           
=======================================
  Files         120      120           
  Lines        8046     8047    +1     
  Branches     1930     1931    +1     
=======================================
+ Hits         6693     6694    +1     
  Misses       1353     1353           

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