Fix base64 decode issue with short signal.me URLs.

app/src/test/java/org/thoughtcrime/securesms/profiles/manage/UsernameRepositoryTest.kt

@@ -0,0 +1,13 @@
+package org.thoughtcrime.securesms.profiles.manage
+
+import assertk.assertThat
+import assertk.assertions.isNull
+import org.junit.Test
+
+class UsernameRepositoryTest {
+  @Test
+  fun parseLink_one_character_base64_ref() {
+    val url = "https://signal.me/#eu/A"
+    assertThat(UsernameRepository.parseLink(url)).isNull()
+  }
+}