show library datasets under correct library name

[AndrewTwydell]

What It Does
Resolves #212 .

This changes the LibraryTreeItems to use a default filter of their Library name so only the Library datasets in that Library show up in that tree. Then it appends the active filter of the library to that filter to search the DSName attribute.

How to Test

Have multiple Library resources with different datasets in. Expand each library. Before this update, they would show the same datasets - now they should show correct datasets.

Review Checklist
I certify that I have:

• tested my changes
• added/updated automated tests
• updated the changelog
• followed the contribution guidelines

Additional Comments

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 0% with 2 lines in your changes missing coverage. Please review.

Project coverage is 28.25%. Comparing base (61f57a8) to head (4d38d6b).

Files with missing lines	Patch %	Lines
...es/vsce/src/trees/treeItems/CICSLibraryTreeItem.ts	0.00%	2 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #213   +/-   ##
=======================================
  Coverage   28.25%   28.25%           
=======================================
  Files         146      146           
  Lines        4987     4986    -1     
  Branches      869      804   -65     
=======================================
  Hits         1409     1409           
+ Misses       3578     3577    -1     

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