refactor: remove literal boolean comparisons leftover from nullsafety conversion

lib/encryption/key_verification_manager.dart

@@ -56,7 +56,7 @@ class KeyVerificationManager {
 
   Future<void> handleToDeviceEvent(ToDeviceEvent event) async {
     if (!event.type.startsWith('m.key.verification.') ||
-        client.verificationMethods.isEmpty != false) {
+        client.verificationMethods.isEmpty) {
       return;
     }
     // we have key verification going on!
@@ -95,7 +95,7 @@ class KeyVerificationManager {
         : event['content']['msgtype'];
     if (type == null ||
         !type.startsWith('m.key.verification.') ||
-        client.verificationMethods.isEmpty != false) {
+        client.verificationMethods.isEmpty) {
       return;
     }
     if (type == EventTypes.KeyVerificationRequest) {

lib/encryption/olm_manager.dart

@@ -57,8 +57,7 @@ class OlmManager {
         await olm.init();
         _olmAccount = olm.Account();
         _olmAccount!.create();
-        if (await uploadKeys(uploadDeviceKeys: true, updateDatabase: false) ==
-            false) {
+        if (!await uploadKeys(uploadDeviceKeys: true, updateDatabase: false)) {
           throw ('Upload key failed');
         }
       } catch (_) {
@@ -359,7 +358,7 @@ class OlmManager {
         if (session.session == null) {
           continue;
         }
-        if (type == 0 && session.session!.matches_inbound(body) == true) {
+        if (type == 0 && session.session!.matches_inbound(body)) {
           try {
             plaintext = session.session!.decrypt(type, body);
           } catch (e) {

lib/encryption/utils/key_verification.dart

@@ -152,10 +152,8 @@ class KeyVerification {
 
   List<String> get knownVerificationMethods {
     final methods = <String>[];
-    if (client.verificationMethods.contains(KeyVerificationMethod.numbers) ==
-            true ||
-        client.verificationMethods.contains(KeyVerificationMethod.emoji) ==
-            true) {
+    if (client.verificationMethods.contains(KeyVerificationMethod.numbers) ||
+        client.verificationMethods.contains(KeyVerificationMethod.emoji)) {
       methods.add('m.sas.v1');
     }
     return methods;
@@ -672,13 +670,11 @@ class _KeyVerificationMethodSas extends _KeyVerificationMethod {
   List<String> get knownAuthentificationTypes {
     final types = <String>[];
     if (request.client.verificationMethods
-            .contains(KeyVerificationMethod.emoji) ==
-        true) {
+        .contains(KeyVerificationMethod.emoji)) {
       types.add('emoji');
     }
     if (request.client.verificationMethods
-            .contains(KeyVerificationMethod.numbers) ==
-        true) {
+        .contains(KeyVerificationMethod.numbers)) {
       types.add('decimal');
     }
     return types;

lib/src/client.dart

@@ -464,7 +464,7 @@ class Client extends MatrixApi {
     @Deprecated('Deprecated in favour of identifier.') String? medium,
     @Deprecated('Deprecated in favour of identifier.') String? address,
   }) async {
-    if (homeserver == null && user != null && user.isValidMatrixId == true) {
+    if (homeserver == null && user != null && user.isValidMatrixId) {
       await checkHomeserver(user.domain);
     }
     final response = await super.login(