copy tooltip on focus. Upgrade PDT version

[peterychang]

Why are these changes needed?

(Partially?) fixes accessibility issue (19). Question out to accessibility team whether its enough.

Migrating to 16.0 for accessibility fixes. Not moving to 16.1 yet because of a weird change to the 'Show Source' link's appearance

Related issue number

#5630

Checks

• I've included any doc changes needed for https://microsoft.github.io/autogen/. See https://github.com/microsoft/autogen/blob/main/CONTRIBUTING.md to build and test documentation locally.
• I've added tests (if relevant) corresponding to the changes introduced in this PR.
• I've made sure all auto checks have passed.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 75.60%. Comparing base (648f734) to head (dbb8ad3).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #5848   +/-   ##
=======================================
  Coverage   75.60%   75.60%           
=======================================
  Files         189      189           
  Lines       12734    12734           
=======================================
  Hits         9627     9627           
  Misses       3107     3107           

Flag	Coverage Δ
unittests	75.60% <ø> (ø)

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