Fix knn query tests as we now do queries with k (#119942)

Since we do the queries with `k` now, need to update the required
feature set for the tests.

The reason for doing the queries with `k` is to ensure coverage since
now we automatically set `k` to `size`

related: https://github.com/elastic/elasticsearch/pull/119700

closes: https://github.com/elastic/elasticsearch/issues/119760 closes:
https://github.com/elastic/elasticsearch/issues/119805 closes:
https://github.com/elastic/elasticsearch/issues/119804

muted-tests.yml

@@ -416,12 +416,6 @@ tests:
 - class: org.elasticsearch.upgrades.SearchStatesIT
   method: testCanMatch
   issue: https://github.com/elastic/elasticsearch/issues/118718
-- class: org.elasticsearch.backwards.MixedClusterClientYamlTestSuiteIT
-  method: "test {p0=search.vectors/110_knn_query_with_filter/PRE_FILTER: knn query with internal filter as pre-filter}"
-  issue: https://github.com/elastic/elasticsearch/issues/119804
-- class: org.elasticsearch.backwards.MixedClusterClientYamlTestSuiteIT
-  method: "test {p0=search.vectors/110_knn_query_with_filter/PRE_FILTER: knn query with alias filter as pre-filter}"
-  issue: https://github.com/elastic/elasticsearch/issues/119805
 - class: org.elasticsearch.backwards.MixedClusterClientYamlTestSuiteIT
   issue: https://github.com/elastic/elasticsearch/issues/119806
 - class: org.elasticsearch.search.profile.dfs.DfsProfilerIT

rest-api-spec/src/yamlRestTest/resources/rest-api-spec/test/search.vectors/110_knn_query_with_filter.yml

@@ -1,8 +1,8 @@
 # test how knn query interacts with filters
 setup:
   - requires:
-      cluster_features: "gte_v8.12.0"
-      reason: 'knn as query added in 8.12'
+      cluster_features: "search.vectors.k_param_supported"
+      reason: 'k param for knn as query is required'
 
   - do:
       indices.create: