refactor!: Remove deployment conf field from VaadinSession

[tepi]

Fixes #18318

[github-actions[bot]]

Test Results

1 045 files  ±  0  1 045 suites  ±0   1h 14m 19s :stopwatch: + 3m 32s 6 736 tests ±  0  6 691 :heavy_check_mark: +  6  45 :zzz: ±0  0 :x:  - 1  7 036 runs  +28  6 980 :heavy_check_mark: +34  56 :zzz: ±0  0 :x:  - 1 

Results for commit c107a81d. ± Comparison against base commit 757c8cba.

:recycle: This comment has been updated with latest results.

[mcollovati]

Some tests to fix, but other than that LGTM

[sonarqubecloud[bot]]

Quality Gate passed

The SonarCloud Quality Gate passed, but some issues were introduced.

3 New issues
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarCloud

[tepi]

Despite approval, do not merge. This should be postponed until major release of Flow (25), since this changes public API.

[mcollovati]

Would it be better to make it a draft again, to prevent unwanted merge?