fix(CollaSet): out of range when extracting available context

[wu8685]

1. Does this PR affect any open issues?(Y/N) and add issue references (e.g. "fix #123", "re #123".):

• N
• Y

2. What is the scope of this PR (e.g. component or file name):

3. Provide a description of the PR(e.g. more details, effects, motivations or doc link):

• Affects user behaviors
• Contains syntax changes
• Contains variable changes
• Contains experimental features
• Performance regression: Consumes more CPU
• Performance regression: Consumes more Memory
• Other

4. Are there any breaking changes?(Y/N) and describe the breaking changes(e.g. more details, motivations or doc link):

• N
• Y

5. Are there test cases for these changes?(Y/N) select and add more details, references or doc links:

• Unit test
• Integration test
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6. Release note

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None

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (a302b54) 62.02% compared to head (0f99181) 61.99%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #139      +/-   ##
==========================================
- Coverage   62.02%   61.99%   -0.03%     
==========================================
  Files          46       46              
  Lines        3573     3573              
==========================================
- Hits         2216     2215       -1     
- Misses       1140     1141       +1     
  Partials      217      217              

Flag	Coverage Δ
unittests	61.99% <ø> (-0.03%)	⬇️

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