[UII] Allow Fleet Fleet post secret and get secret to accept array of strings

[jen-huang]

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[Copilot]

Pull Request Overview

This PR updates the Fleet secret APIs to allow storing and retrieving secrets as an array of strings in addition to a single string. Key changes include updating the secret request/response classes to support multiple value types, adding appropriate parser logic, and extending YAML tests to cover the multi-value scenarios.

Reviewed Changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
x-pack/plugin/fleet/src/main/java/org/elasticsearch/xpack/fleet/action/TransportGetSecretAction.java	Adjusts GET secret handling to support a list of strings
x-pack/plugin/fleet/src/main/java/org/elasticsearch/xpack/fleet/action/PostSecretRequest.java	Updates parsing, serialization, and validation to handle multi-value secrets
x-pack/plugin/fleet/src/main/java/org/elasticsearch/xpack/fleet/action/GetSecretResponse.java	Modifies response serialization to support returning a string array
x-pack/plugin/fleet/qa/rest/src/yamlRestTest/resources/rest-api-spec/test/fleet/40_secrets_get.yml	Adds integration test for retrieving multi-value secrets
x-pack/plugin/fleet/qa/rest/src/yamlRestTest/resources/rest-api-spec/test/fleet/30_secrets_post.yml	Adds integration test for creating multi-value secrets
x-pack/plugin/fleet/src/test/java/org/elasticsearch/xpack/fleet/action/PostSecretRequestTests.java	Introduces unit tests for validating behavior with multiple and invalid secret values

Comments suppressed due to low confidence (1)

x-pack/plugin/fleet/src/main/java/org/elasticsearch/xpack/fleet/action/PostSecretRequest.java:60

• The StreamInput deserialization only reads a String, which does not support the new array type. Update the deserialization logic to distinguish between a single string and an array of strings.

this.value = in.readString();

[Copilot]

The StreamInput deserialization for 'value' only handles a single String. When a multi-value secret is returned, the stream reading should be updated to properly deserialize a String array.

Suggested change

	this.value = in.readString();
	if (in.readBoolean()) {
	this.value = in.readString();
	} else {
	this.value = in.readStringArray();
	}