Update header names for Camel 4.18.3 header renames

[Croway]

Summary

• Update Kafka header names from kafka.* to CamelKafka* prefix (kafka-sink, kafka-apicurio-registry-not-secured-sink, kafka-not-secured-apicurio-registry-sink, kafka-azure-schema-registry-sink, set-kafka-key-action)
• Update Elasticsearch header names from indexId/indexName to CamelElasticsearchIndexId/CamelElasticsearchIndexName
• Update Opensearch header names from indexId/indexName to CamelOpensearchIndexId/CamelOpensearchIndexName
• Update Salesforce header names from sObjectId/sObjectName to CamelSalesforceSObjectId/CamelSalesforceSObjectName in setHeader/removeHeader (endpoint options unchanged)
• Update Kafka header names in integration test files

Follows the header renames documented in the 4.18.x upgrade guide (4.18.1 → 4.18.3 section). Complements #2876 which only covered the SMT kamelets.

Test plan

• Verify kamelets/ and library/ copies are identical
• Verify no old header names remain in kamelet definitions
• Integration tests pass with updated header names