test: add test cases for invalid pagination key

[170210]

Description

Add a test case in some function because we have not tested if pagination key is invalid.
This PR has added tests for invalid pagination key in 3 functions, except contractsByCode(contractsByCode has not been tested, it will be fixed in another PR )

Motivation and context

How has this been tested?

Unit tests

Screenshots (if appropriate):

Checklist:

• I followed the contributing guidelines and code of conduct.
• I have added a relevant changelog to CHANGELOG.md
• I have added tests to cover my changes.
• I have updated the documentation accordingly.
• I have updated API documentation client/docs/swagger-ui/swagger.yaml

[codecov]

Codecov Report

Merging #66 (5002d81) into main (1f60af6) will decrease coverage by 0.13%.
The diff coverage is n/a.

❗ Current head 5002d81 differs from pull request most recent head cb46df2. Consider uploading reports for the commit cb46df2 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #66      +/-   ##
==========================================
- Coverage   62.21%   62.09%   -0.13%     
==========================================
  Files          80       80              
  Lines        9971     9971              
==========================================
- Hits         6203     6191      -12     
- Misses       3438     3446       +8     
- Partials      330      334       +4     

see 2 files with indirect coverage changes