chore: fix log message in Hotswapper

[mcollovati]

Description

Fixes the Hotswapper log message to print the changed class instead of listing all the classes referenced by endpoints.

Type of change

• Bugfix
• Feature

Checklist

• I have read the contribution guide: https://vaadin.com/docs/latest/guide/contributing/overview/
• I have added a description following the guideline.
• The issue is created in the corresponding repository and I have referenced it.
• I have added tests to ensure my change is effective and works as intended.
• New and existing tests are passing locally with my change.
• I have performed self-review and corrected misspellings.

Additional for Feature type of change

• Enhancement / new feature was discussed in a corresponding GitHub issue and Acceptance Criteria were created.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 92.28%. Comparing base (45a53d9) to head (0cb6eb2).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2677   +/-   ##
=======================================
  Coverage   92.28%   92.28%           
=======================================
  Files          76       76           
  Lines        2477     2477           
  Branches      643      643           
=======================================
  Hits         2286     2286           
  Misses        144      144           
  Partials       47       47           

Flag	Coverage Δ
unittests	92.28% <ø> (ø)

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[taefi]

LGTM, and probably doesn't need adding tests.

[sonarcloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud