fix(ci): drop hardcoded Windows java.io.tmpdir override in Gradle

The gen/android/gradle.properties carried a committed local-only override
-Djava.io.tmpdir=D:\tmp\win-temp which crashes Gradle on Ubuntu CI
("java.io.tmpdir is set to a directory that doesn't exist"). Without the
override, Gradle uses %TEMP% on Windows and /tmp on Linux — both valid.
If a local override is needed again, put it in ~/.gradle/gradle.properties
so it doesn't leak into the shared repo.

Author: Rwanbt

packages/mobile/src-tauri/gen/android/gradle.properties

@@ -6,7 +6,7 @@
 # http://www.gradle.org/docs/current/userguide/build_environment.html
 # Specifies the JVM arguments used for the daemon process.
 # The setting is particularly useful for tweaking memory settings.
-org.gradle.jvmargs=-Xmx2048m -Dfile.encoding=UTF-8 -Djava.io.tmpdir=D:\\tmp\\win-temp
+org.gradle.jvmargs=-Xmx2048m -Dfile.encoding=UTF-8
 # When configured, Gradle will run in incubating parallel mode.
 # This option should only be used with decoupled projects. More details, visit
 # http://www.gradle.org/docs/current/userguide/multi_project_builds.html#sec:decoupled_projects