[opamp-client] Remove CompletableFuture usage

[breedx-splk]

See this comment about the gummy bears upgrade change for context.

The tools were quick to point out that the async ritual and use of CompletableFuture wasn't really that helpful because the caller immediately turned around and called .get(30) or whatever on the future anyway....effectively making it synchronous.

(slopvomited with codex)

[Copilot]

Pull request overview

This PR removes the now-effectively-synchronous CompletableFuture-based HTTP sending flow in opamp-client and replaces it with a synchronous HttpSender API, aligning the implementation with how callers were already using it (blocking on the future).

Changes:

• Change HttpSender.send(...) to return Response directly (no CompletableFuture).
• Update HttpRequestService and OkHttpSender to use a synchronous request/response flow (with a per-call timeout configured in OkHttp).
• Update tests and bump the animalsniffer gummy-bears signature to 0.14.0.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
opamp-client/src/main/java/io/opentelemetry/opamp/client/internal/request/service/HttpRequestService.java	Switch request execution to synchronous HttpSender.send(...) and simplify exception handling.
opamp-client/src/main/java/io/opentelemetry/opamp/client/internal/connectivity/http/OkHttpSender.java	Implement synchronous OkHttp call execution with a 30s call timeout.
opamp-client/src/main/java/io/opentelemetry/opamp/client/internal/connectivity/http/HttpSender.java	Update sender interface to synchronous return type and add declared checked exceptions.
opamp-client/src/test/java/io/opentelemetry/opamp/client/internal/request/service/HttpRequestServiceTest.java	Adapt tests and test sender to the synchronous API and new exception behavior.
buildSrc/src/main/kotlin/otel.animalsniffer-conventions.gradle.kts	Update gummy-bears signature version to 0.14.0.

[LikeTheSalad]

Cheers!