Remove setup variant for Java OpenTelemetry agentless setup (#14409)

`-Dotel.java.global-autoconfigure.enabled=true` alone leads to lazy init
of the OpenTelemetry SDK.
If Sentry API is used before any OpenTelemetry API then calls like
`Sentry.captureMessage` etc. don't work.
We'd have to ensure eager init of the OpenTelemetry SDK in order to have
Sentry initialized early like this:
```
import io.opentelemetry.sdk.autoconfigure.AutoConfiguredOpenTelemetrySdk;

class Main {
  static {
    AutoConfiguredOpenTelemetrySdk.initialize();
  }
}
```

Due to this requiring the `java` arg AND code, it's easier to just rely
on the second method in docs that only need code changes.

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Author: adinauer

platform-includes/performance/opentelemetry-setup/without-java-agent/java.mdx

@@ -1,12 +1,6 @@
 #### Initializing OpenTelemetry
 
-Our `sentry-opentelemetry-agentless` dependency also adds `opentelemetry-sdk-extension-autoconfigure` which takes care of configuring OpenTelemetry to work with Sentry. There's two ways to trigger it.
-
-1. Using a property on startup
-
-Add `-Dotel.java.global-autoconfigure.enabled=true` to the `java` command when starting your application.
-
-2. Using `AutoConfiguredOpenTelemetrySdk`
+Our `sentry-opentelemetry-agentless` dependency also adds `opentelemetry-sdk-extension-autoconfigure` which takes care of configuring OpenTelemetry to work with Sentry. You can configure it using `AutoConfiguredOpenTelemetrySdk`:
 
 ```java {tabTitle: Java}
 import io.opentelemetry.sdk.autoconfigure.AutoConfiguredOpenTelemetrySdk;