[libc++][Android] Don't list Android as supported yet (#69660)

We don't have a pre-commit CI bot running Android tests yet, so this is still WIP.

Author: rprichard

libcxx/docs/index.rst

@@ -130,7 +130,6 @@ Target platform Target architecture       Notes
 macOS 10.9+     i386, x86_64, arm64       Building the shared library itself requires targetting macOS 10.13+
 FreeBSD 12+     i386, x86_64, arm
 Linux           i386, x86_64, arm, arm64  Only glibc-2.24 and later and no other libc is officially supported
-Android 5.0+    i386, x86_64, arm, arm64
 Windows         i386, x86_64              Both MSVC and MinGW style environments, ABI in MSVC environments is :doc:`unstable <DesignDocs/ABIVersioning>`
 AIX 7.2TL5+     powerpc, powerpc64
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