fix: Android - Remove Disk Buffering (#315)

## Summary

Remove Disk buffering seems failing. Let's just delete it.


<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> Removes OpenTelemetry disk buffering setup and its helper from
`InstrumentationManager`.
> 
> - **Observability Android SDK**:
> - Remove disk buffering configuration from `createOtelRumConfig()` in
`InstrumentationManager.kt` (drop `DiskBufferingConfig` setup).
>   - Delete unused helper `isAnySignalEnabled(options)`.
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
10aa487. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

Author: abelonogov-ld

sdk/@launchdarkly/observability-android/lib/src/main/kotlin/com/launchdarkly/observability/client/InstrumentationManager.kt

@@ -148,12 +148,6 @@ class InstrumentationManager(
 
     private fun createOtelRumConfig(): OtelRumConfig {
         val config = OtelRumConfig()
-            .setDiskBufferingConfig(
-                DiskBufferingConfig.create(
-                    enabled = isAnySignalEnabled(options),
-                    debugEnabled = options.debug
-                )
-            )
             .setSessionConfig(SessionConfig(backgroundInactivityTimeout = options.sessionBackgroundTimeout))
 
         if (options.disableErrorTracking) {
@@ -165,10 +159,6 @@ class InstrumentationManager(
         return config
     }
 
-    private fun isAnySignalEnabled(options: Options): Boolean {
-        return !options.disableLogs || !options.disableTraces || !options.disableMetrics || !options.disableErrorTracking
-    }
-
     private fun configureTracerProvider(sdkTracerProviderBuilder: SdkTracerProviderBuilder): SdkTracerProviderBuilder {
         val primarySpanExporter = createOtlpSpanExporter()
         sdkTracerProviderBuilder