wasm: remove redundant xds attributes

[kyessenov]

Change-Id: I152e259f3f8e5f69463a64fedce4181ce606824b

Commit Message: Remove attributes that were marked as deprecated in https://github.com/envoyproxy/envoy/commit/ff991f3454b426bfec49c752d1e7ffbafa9fdd76. This improves the alignment of get_property ABI with the generic attribute support in Envoy in CEL, for example, and simplifies the implementation.

Additional Description: Risk Level: low, experimental filter, advanced warning to stop using attributes was given Testing: updated Docs Changes: yes Release Notes: yes

[kyessenov]

/coverage

[repokitteh-read-only[bot]]

Coverage for this Pull Request will be rendered here:

https://storage.googleapis.com/envoy-pr/36619/coverage/index.html

The coverage results are (re-)rendered each time the CI envoy-presubmit (check linux_x64 coverage) job completes.

:cat:

Caused by: a https://github.com/envoyproxy/envoy/pull/36619#issuecomment-2417283691 was created by @kyessenov.

see: more, trace.

[tyxia]

/assign @mpwarres, based on CODEOWNER

[repokitteh-read-only[bot]]

neither of @mpwarres,, based, on, CODEOWNER can be assigned to this issue.

:cat:

Caused by: a https://github.com/envoyproxy/envoy/pull/36619#issuecomment-2417685165 was created by @tyxia.

see: more, trace.

[tyxia]

/assign @mpwarres

based on CODEOWNER

[tyxia]

Side note: @kyessenov @alyssawilk looks like WSAM doesn't have maintainer sponsor currently given Lizan has left? https://github.com/envoyproxy/envoy/blob/main/CODEOWNERS#L106-L116

[kyessenov]

I'm willing to sponsor the improvements to Wasm, as previously discussed.