Added agent_id tracking in agent reporter collection

[AgrimGupta04]

This PR enhances the agent data collection process by ensuring that each agent reporter includes a unique identifier, the agent_id in the collected data.
Also, agent_reporters previously collected only the values of the requested columns (eg- wealth) but now includes the unique agent_id making debugging and analysis easier.
This PR solving the issue #177

[adamamer20]

Hi Agrim, thanks for the PR!
A couple of notes:

1. Please remove the unused result import from unittest, since it is not referenced anywhere.

2. Several hasattr(...) checks, such as hasattr(agent_set, "df"), add unnecessary defensive code and reduce readability. Switch to direct attribute access and rely on the object contract instead.

Before pushing the next commit, run the test suite locally with pytest and resolve any failures. As a hint, the current failure seems related to the shape of the DataFrame.

[codecov]

Codecov Report

❌ Patch coverage is 95.45455% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 92.62%. Comparing base (33555b4) to head (622af26).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
mesa_frames/concrete/datacollector.py	95.45%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #182      +/-   ##
==========================================
+ Coverage   92.54%   92.62%   +0.07%     
==========================================
  Files          14       14              
  Lines        1717     1748      +31     
==========================================
+ Hits         1589     1619      +30     
- Misses        128      129       +1     

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