Change HTTP method to POST when using the API login endpoint

[mcarmona99]

This issue is part of wazuh/wazuh#12793.

The epic issue aims to change the API login endpoint method from GET to POST, as using GET as the method of a login endpoint is incorrect.

As it was said in wazuh/wazuh#10203 (comment), both GET /security/user/authenticate and POST /security/user/authenticate endpoints will coexist and the deprecation of GET /security/user/authenticate will happen in a future major release.

To avoid future problems when the actual login endpoint (GET) is deprecated, we should update all the references found in this repository:

https://github.com/wazuh/wazuh-kibana-app/blob/0f8c255f57d9505f9d197dae6b9bb28e7cf2cdf9/server/lib/api-interceptor.ts#L49-L60

https://github.com/wazuh/wazuh-kibana-app/blob/0f8c255f57d9505f9d197dae6b9bb28e7cf2cdf9/scripts/generate-api-4.0-info/generate-api-4.0-info.js#L113

Login endpoint inside the GET key in https://github.com/wazuh/wazuh-kibana-app/blob/0f8c255f57d9505f9d197dae6b9bb28e7cf2cdf9/common/api-info/endpoints.json and https://github.com/wazuh/wazuh-kibana-app/blob/0f8c255f57d9505f9d197dae6b9bb28e7cf2cdf9/server/lib/api-request-list.json.