Eliminate remaining Electron 8 deprecations

* Change systemPreferences.isDarkMode() to nativeTheme.shouldUseDarkColors

* Remove vibrancy parameter to BrowserWindow

* Update curve25519-n; removes context-aware deprecation warning

* Set app.allowRendererProcessReuse = true to remove warning

* Move from deprecated setters to direct property set

* Serialized sender certificates: Store less, store plain object

* isMenuBarAutoHide -> autoHideMenuBar

* UUID: Fix sealed sender indicator on message details screen

* Data._cleanData: Remove function keys, handle null in array

Also:
- run _cleanData when saving attachment download jobs
- remove job from jobs table when the send itself throws error

* _cleanData: Don't dig into strings, booleans, or numbers

* getPropsForMessageDetail: Make it clear what we're reducing

Co-authored-by: Ken Powers <ken@signal.org>

test/metadata/SecretSessionCipher_test.js

@@ -170,7 +170,7 @@ describe('SecretSessionCipher', () => {
 
     const ciphertext = await aliceCipher.encrypt(
       new libsignal.SignalProtocolAddress('+14152222222', 1),
-      senderCertificate,
+      { serialized: senderCertificate.serialized },
       bytesFromString('smert za smert')
     );
 
@@ -212,7 +212,7 @@ describe('SecretSessionCipher', () => {
 
     const ciphertext = await aliceCipher.encrypt(
       new libsignal.SignalProtocolAddress('+14152222222', 1),
-      senderCertificate,
+      { serialized: senderCertificate.serialized },
       bytesFromString('и вот я')
     );
 
@@ -252,7 +252,7 @@ describe('SecretSessionCipher', () => {
 
     const ciphertext = await aliceCipher.encrypt(
       new libsignal.SignalProtocolAddress('+14152222222', 1),
-      senderCertificate,
+      { serialized: senderCertificate.serialized },
       bytesFromString('и вот я')
     );
 
@@ -291,7 +291,7 @@ describe('SecretSessionCipher', () => {
 
     const ciphertext = await aliceCipher.encrypt(
       new libsignal.SignalProtocolAddress('+14152222222', 1),
-      senderCertificate,
+      { serialized: senderCertificate.serialized },
       bytesFromString('smert za smert')
     );