☀️ feat: Enhancing OpenIM with Integrated E2E Testing and CI/CD Enhancements

[cubxxw]

🔍 What type of PR is this?

👀 What this PR does / why we need it:

• My pull request adheres to the code style of this project
• My code requires changes to the documentation
• I have updated the documentation as required
• All the tests have passed

🅰 Which issue(s) this PR fixes:

Fixes #1119
Resolves #1355, resolves #1357

📝 Special notes for your reviewer:

We encourage contributions from community members who have experience with E2E testing and CI/CD practices. Suggestions for testing tools, test cases, and CI integration strategies are most welcome.

🎯 Describe how to verify it

1. CICD
2. local(codespaces ci)

make test-api
make test-e2e

📑 Additional documentation e.g., RFC, notion, Google docs, usage docs, etc.:

This issue outlines the need for comprehensive E2E testing within the OpenIMSDK/Open-IM-Server repository. The implementation plan provided aims to guide the setup, development, and integration of E2E tests into the CI pipeline, ensuring rigorous testing standards and maintaining system reliability as the project evolves.

[pull-request-size]

Whoa! Easy there, Partner!

This PR is too big. Please break it up into smaller PRs.

[kubbot]

CLA Assistant Lite bot 🤖 All Contributors have signed the open-im-server CLA.
The signed information is recorded 🤖here

[sweep-ai]

Apply Sweep Rules to your PR?

• Apply: All new business logic should have corresponding unit tests.
• Apply: Refactor large functions to be more modular.

[codecov]

Codecov Report

Merging #1359 (4a38dc6) into main (a32e94b) will increase coverage by 3.19%.
Report is 1 commits behind head on main.
The diff coverage is 79.48%.

@@           Coverage Diff            @@
##            main   #1359      +/-   ##
========================================
+ Coverage   2.41%   5.61%   +3.19%     
========================================
  Files         13      23      +10     
  Lines        786    1353     +567     
========================================
+ Hits          19      76      +57     
- Misses       764    1273     +509     
- Partials       3       4       +1     

Files	Coverage Δ
pkg/common/db/relation/conversation_model.go	0.00% <ø> (ø)
pkg/common/discoveryregister/discoveryregister.go	0.00% <ø> (ø)
test/e2e/e2e.go	100.00% <100.00%> (ø)
test/e2e/framework/config/config.go	100.00% <100.00%> (ø)
pkg/common/startrpc/start.go	21.05% <33.33%> (ø)
pkg/common/config/parse.go	0.00% <0.00%> (ø)
pkg/common/prommetrics/prommetrics.go	42.85% <0.00%> (ø)

... and 4 files with indirect coverage changes