Remove some non-determinism

[licaon-kter]

ArcaneChat is reproducible in F-Droid, while your app is not built reproducible we continuously test older versions on https://verification.f-droid.org/?C=M;O=D and would like more and more apps to become repro

take this latest verification: https://verification.f-droid.org/com.b44t.messenger_7091.apk.diffoscope.html

this needs at least the build-id being removed: https://verification.f-droid.org/com.b44t.messenger_7091.apk.diffoscope.html#lib-armeabi-v-a-libnative-utils.so

and the build date: https://verification.f-droid.org/com.b44t.messenger_7091.apk.diffoscope.html#lib-armeabi-v-a-libnative-utils.so---strings---all---bytes-----

since this touches a bit more of the build process I've not opened a PR, but you can use the Arcane as a guide: eg. ArcaneChat/android@2ce614d and ArcaneChat/android@2376777