Raise when the dependency set size changes while fetching the agent

[angrybayblade]

Proposed changes

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Fixes

fixes #631

Types of changes

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• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist

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• I have read the CONTRIBUTING doc
• I am making a pull request against the develop branch (left side). Also you should start your branch off our develop.
• Lint and unit tests pass locally with my changes and CI passes too
• I have added tests that prove my fix is effective or that my feature works
• I have checked that code coverage does not decrease.
• I have added necessary documentation (if appropriate)
• Any dependent changes have been merged and published in downstream modules

Further comments

If this is a relatively large or complex change, kick off the discussion by explaining why you chose the solution you did and what alternatives you considered, etc...

DELETE INCLUSIVE THIS AND BELOW FOR STANDARD PR

Release summary

Version number: [e.g. 1.0.1]

Release details

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Checklist

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• I have read the CONTRIBUTING doc
• I am making a pull request against the main branch (left side), from develop
• Lint and unit tests pass locally and in CI
• I have checked the fingerprint hashes are correct by running (aea packages lock --check)
• I have regenerated the latest API docs
• I built the documentation and updated it with the latest changes
• I have added an item in HISTORY.md for this release
• I bumped the version number in the aea/__version__.py file.
• I bumped the version number in every Docker image of the repo and published it. Also, I built and published them with tag latest
  (check the READMEs of aea-develop
  and aea-user)
• I have pushed the latest packages to the registry.
• I have uploaded the latest aea to PyPI.
• I have uploaded the latest plugins to PyPI.

Further comments

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[codecov-commenter]

Codecov Report

Attention: 3 lines in your changes are missing coverage. Please review.

Comparison is base (2be89a7) 91.99% compared to head (0364195) 91.98%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #675      +/-   ##
==========================================
- Coverage   91.99%   91.98%   -0.01%     
==========================================
  Files         371      371              
  Lines       29539    29545       +6     
==========================================
+ Hits        27175    27178       +3     
- Misses       2364     2367       +3     

Flag	Coverage Δ
unittests	91.98% <66.66%> (-0.01%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
aea/cli/fetch.py	94.35% <66.66%> (-2.26%)	⬇️

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