Improve deployment related error messages

[feluelle]

Description

Describe the purpose of this pull request.

Improve deployment-related error messages, fix typos, and remove unused ones.

cc @paolaperaza

🎟 Issue(s)

Related #1537 (review)

🧪 Functional Testing

List the functional testing steps to confirm this feature or fix.

📸 Screenshots

Add screenshots to illustrate the validity of these changes.

📋 Checklist

• Rebased from the main (or release if patching) branch (before testing)
• Ran make test before taking out of draft
• Ran make lint before taking out of draft
• Added/updated applicable tests
• Tested against Astro-API (if necessary).
• Tested against Houston-API and Astronomer (if necessary).
• Communicated to/tagged owners of respective clients potentially impacted by these changes.
• Updated any related documentation

[codecov]

Codecov Report

Attention: 1 lines in your changes are missing coverage. Please review.

Comparison is base (f47a24a) 86.16% compared to head (91b9479) 86.16%.
Report is 1 commits behind head on main.

Files	Patch %	Lines
cloud/deployment/deployment.go	0.00%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1555   +/-   ##
=======================================
  Coverage   86.16%   86.16%           
=======================================
  Files         112      112           
  Lines       14952    14952           
=======================================
  Hits        12883    12883           
  Misses       1251     1251           
  Partials      818      818           

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