The app module named no NDK, so AGP expected its default 27.0 against the 26.1 that CI installs,
could not strip any native library and made no native-debug-symbols.zip for Play. Pin 26.1 in the
app. The light client now keeps line tables for that symbol file; the packaged library is still
stripped to 8.6 MB.
Also adds an XCM encoding test for PezkuwiChain networks. This commit points WESTEND at Zagros
to check that the test fails against that change.