Fix test_browse_website

[Pwuts]

Background

test_browse_website sometimes breaks unnecessarily: https://github.com/Significant-Gravitas/Auto-GPT/actions/runs/5495512754/jobs/10014962625

Changes

• Convert the result to lowercase before checking, so that "error" and "Error" don't cause a mismatch

Test Plan

CI

PR Quality Checklist

• My pull request is atomic and focuses on a single change.
• I have thoroughly tested my changes with multiple different prompts.
• I have considered potential risks and mitigations for my changes.
• I have documented my changes clearly and comprehensively.
• I have not snuck in any "extra" small tweaks changes.
• I have run the following commands against my code to ensure it passes our linters:

  black .
  isort .
  mypy
  autoflake --remove-all-unused-imports --recursive --ignore-init-module-imports --ignore-pass-after-docstring autogpt tests --in-place

[netlify]

✅ Deploy Preview for auto-gpt-docs canceled.

Name	Link
🔨 Latest commit	3c904cd
🔍 Latest deploy log	https://app.netlify.com/sites/auto-gpt-docs/deploys/64aac0f4e10fbb0008f81793

[Auto-GPT-Bot]

You changed AutoGPT's behaviour. The cassettes have been updated and will be merged to the submodule when this Pull Request gets merged.

[codecov]

Codecov Report

Patch coverage: 100.00% and no project coverage change.

Comparison is base (f6da992) 50.55% compared to head (3c904cd) 50.56%.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #4925   +/-   ##
=======================================
  Coverage   50.55%   50.56%           
=======================================
  Files         116      115    -1     
  Lines        4860     4790   -70     
  Branches      657      636   -21     
=======================================
- Hits         2457     2422   -35     
+ Misses       2219     2192   -27     
+ Partials      184      176    -8     

Impacted Files	Coverage Δ
autogpt/agent/__init__.py	100.00% <100.00%> (ø)

☔ View full report in Codecov by Sentry.
📢 Do you have feedback about the report comment? Let us know in this issue.