feat(crypto): BackupDecryptionKey and DehydratedDeviceKey implement Default.

Author: Hywan

crates/matrix-sdk-crypto/src/store/mod.rs

@@ -754,6 +754,12 @@ impl BackupDecryptionKey {
     }
 }
 
+impl Default for BackupDecryptionKey {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 #[cfg(not(tarpaulin_include))]
 impl Debug for BackupDecryptionKey {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
@@ -812,6 +818,12 @@ impl DehydratedDeviceKey {
     }
 }
 
+impl Default for DehydratedDeviceKey {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 impl From<&[u8; 32]> for DehydratedDeviceKey {
     fn from(value: &[u8; 32]) -> Self {
         DehydratedDeviceKey { inner: Box::new(*value) }