[DDO-3290] Stop escaping text sent to Slack's API

[jack-r-warren]

All the mocks in the world don't help if you're explicitly telling the Slack library to escape the all-important < and > characters. Whatever.

Testing

Well I dove into the library code to see that it was explicitly escaping "<" and ">". I don't know, I think trying to write tests around the library's outward HTTP behavior is more brittle than it is worth.

Risk

Very low.

[sonarqubecloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

No Coverage information
0.0% Duplication

[github-actions]

What's Deleted

---

POST /api/deploy-hooks/github-actions/procedures/v3/test/{selector}

Test a GithubActionsDeployHook

POST /api/deploy-hooks/slack/procedures/v3/test/{selector}

Test a SlackDeployHook

[github-actions]

Published image from 47a15b2 (merge 0dba80b):

us-central1-docker.pkg.dev/dsp-artifact-registry/sherlock/sherlock:v0.2.34-0dba80b

[codecov]

Codecov Report

Merging #350 (47a15b2) into main (82aeff1) will increase coverage by 0.12%.
Report is 7 commits behind head on main.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main     #350      +/-   ##
==========================================
+ Coverage   65.48%   65.60%   +0.12%     
==========================================
  Files         149      151       +2     
  Lines        8749     8853     +104     
==========================================
+ Hits         5729     5808      +79     
- Misses       2619     2636      +17     
- Partials      401      409       +8     

Files	Coverage Δ
sherlock/internal/slack/send_message.go	100.00% <ø> (ø)

... and 4 files with indirect coverage changes