[db] don't allow initial repos from fixtures to provide weight

The client was already auto-incrementing their weight anyway. But it leaked our internal weight handling into the library consumer which can cause issues like when me are making changes to how we handles repo weights as we are doing now.

libs/database/src/dbTest/java/org/fdroid/database/RepositoryDaoTest.kt

@@ -30,7 +30,6 @@ internal class RepositoryDaoTest : DbTest() {
             certificate = "abcdef", // not random, because format gets checked
             version = Random.nextLong(),
             enabled = Random.nextBoolean(),
-            weight = Random.nextInt(),
         )
         val repoId = repoDao.insert(repo)
 
@@ -41,7 +40,7 @@ internal class RepositoryDaoTest : DbTest() {
         assertEquals(repo.certificate, actualRepo.certificate)
         assertEquals(repo.version, actualRepo.version)
         assertEquals(repo.enabled, actualRepo.enabled)
-        assertEquals(repo.weight, actualRepo.weight)
+        assertEquals(Int.MAX_VALUE - 2, actualRepo.weight) // ignoring provided weight
         assertEquals(-1, actualRepo.timestamp)
         assertEquals(3, actualRepo.mirrors.size)
         assertEquals(emptyList(), actualRepo.userMirrors)