ref(react-native): remove dsn as main group. (#15620)

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The grouping makes no sense at the moment, My fix is to replace the
"dsn" group by "core options"

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Author: lucas-zimerman

docs/platforms/react-native/configuration/options.mdx

@@ -6,12 +6,14 @@ sidebar_order: 1
 
 <PlatformContent includePath="configuration/config-intro" />
 
-## Core Options
+## Available Options
 
-<TableOfContents ignoreIds={["core-options"]} />
+<TableOfContents ignoreIds={["available-options"]} />
 
 Options that can be read from an environment variable (`SENTRY_DSN`, `SENTRY_ENVIRONMENT`, `SENTRY_RELEASE`) are read automatically.
 
+## Core Options
+
 <SdkOption name="dsn">
 
 The DSN tells the SDK where to send the events. If this value is not provided, the SDK will try to read it from the `SENTRY_DSN` environment variable. If that variable also does not exist, the SDK will just not send any events.