build: do not specify NDK path in WORKSPACE file (#1669)

Relying on the env variable makes local builds easier

Signed-off-by: Snow Pettersen <snowp@lyft.com>
Signed-off-by: JP Simard <jp@jpsim.com>

mobile/WORKSPACE

@@ -45,7 +45,7 @@ declare_python_abi(name = "python_abi", python_version = "3")
 
 # Note: proguard is failing for API 30+
 android_sdk_repository(name = "androidsdk", api_level = 29)
-android_ndk_repository(name = "androidndk", path = "/Users/runner/Library/Android/sdk/ndk/21.3.6528147", api_level = 21)
+android_ndk_repository(name = "androidndk", api_level = 21)
 
 load("@bazel_tools//tools/build_defs/repo:git.bzl", "git_repository")