Add snapshot repository setup for Java Feature Flags SDK (#2201)

* Initial plan

* Add snapshot version setup documentation for Java Feature Flags SDK

Co-authored-by: msiebert <[email protected]>

* Simplify snapshot version setup by linking to Sonatype docs instead of inlining

Co-authored-by: msiebert <[email protected]>

* Remove 'Installing the SDK' header

---------

Co-authored-by: copilot-swe-agent[bot] <[email protected]>
Co-authored-by: msiebert <[email protected]>
Co-authored-by: Mark Siebert <[email protected]>

Author: Copilot

pages/docs/tracking-methods/sdks/java/java-flags.mdx

@@ -17,6 +17,10 @@ Before implementing [Feature Flags](/docs/featureflags), ensure:
 - You are on an Enterprise subscription plan and have the appropriate version of the SDK installed (minimum supported version is `1.6.0-SNAPSHOT`). If not, please follow [this doc](/docs/quickstart/install-mixpanel) to install the SDK.
 - You have your Project Token from your [Mixpanel Project Settings](/docs/orgs-and-projects/managing-projects#find-your-project-tokens)
 
+<Callout type="info">
+  The Java Feature Flags SDK is currently in Beta and uses a `-SNAPSHOT` version (`1.6.0-SNAPSHOT`). You'll need to configure your build tool to pull snapshot versions from Sonatype's snapshot repository. See the [Sonatype snapshot documentation](https://central.sonatype.org/publish/publish-portal-snapshots/) for instructions on configuring Maven or Gradle.
+</Callout>
+
 ## Flag Evaluation Modes
 
 There are two modes available for using the Java SDK for feature flagging: Local Evaluation and Remote Evaluation.