minor #53462 [ProxyManagerBridge] Adding info about discontinuation (ThomasLandauer)

This PR was squashed before being merged into the 6.4 branch.

Discussion
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[ProxyManagerBridge] Adding info about discontinuation

| Q             | A
| ------------- | ---
| Branch?       | 6.4
| Bug fix?      | no
| New feature?  | no
| Deprecations? | no
| Issues        |
| License       | MIT

Commits
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62e0985b70 [ProxyManagerBridge] Adding info about discontinuation