DbxUserFilesRequests#searchV2 fails on Android when query contains > 2 Chinese characters

Hey Dropbox Team,

I'm encountering some unexpected behavior when using the Java SDK's files/search_v2 method on the Android platform, specifically with Chinese filenames.

The DbxUserFilesRequests#searchV2(String query) call on Android fails when the query contains **more than two Chinese characters**. The search **succeeds** if the query has **two or fewer** Chinese characters.

**Environment**

- SDK: com.dropbox.core:dropbox-core-sdk:7.0.0
- SDK: com.dropbox.core:dropbox-android-sdk:7.0.0

- Platform: Android

- API: /files/search_v2

Could you please take a look at the query string processing and encoding logic for Chinese characters within the Android SDK?

Thank you for your time.

Start at DbxUserFilesRequests#searchV2(String query) and trace the query-string processing and encoding used by the Android SDK for /files/search_v2. Reproduce the behavior with the stated SDK 7.0.0 versions and Chinese filenames; done means searches with more than two Chinese characters succeed on Android without regressing shorter queries.

Written by the indexing model from the issue text.