Fix operator image displaying for GVA messages

Previously operator image view was displayed for each GVA message. This commit make it work in the next way as it works with regular messages:
```
  gvaMessage
  gvaMessage
  gvaMessage
🧑gvaMessage
            visitorMessage
  gvaMessage
🧑gvaMessage
```
Also SecureConversations.TranscriptModel class was moved to separate file.

MOB-2512

GliaWidgets.xcodeproj/project.pbxproj

@@ -394,6 +394,7 @@
 		8491AF482A94EE8700CC3E72 /* ConfigurationDeeplinkHandlerTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 8491AF472A94EE8700CC3E72 /* ConfigurationDeeplinkHandlerTests.swift */; };
 		8491AF4E2A9CB3A400CC3E72 /* SecureConversations.TranscriptModel+GVA.swift in Sources */ = {isa = PBXBuildFile; fileRef = 8491AF4D2A9CB3A400CC3E72 /* SecureConversations.TranscriptModel+GVA.swift */; };
 		8491AF502A9CBB0400CC3E72 /* TranscriptModelTests+GVA.swift in Sources */ = {isa = PBXBuildFile; fileRef = 8491AF4F2A9CBB0400CC3E72 /* TranscriptModelTests+GVA.swift */; };
+		8491AF522A9F813200CC3E72 /* SecureConversations.TranscriptModel.swift in Sources */ = {isa = PBXBuildFile; fileRef = 8491AF512A9F813200CC3E72 /* SecureConversations.TranscriptModel.swift */; };
 		84A318A12869ECFC00CA1DE5 /* Unavailable.swift in Sources */ = {isa = PBXBuildFile; fileRef = 84A318A02869ECFC00CA1DE5 /* Unavailable.swift */; };
 		84CFB7732822700000167258 /* Theme.Button.Accessibility.swift in Sources */ = {isa = PBXBuildFile; fileRef = 84CFB7722822700000167258 /* Theme.Button.Accessibility.swift */; };
 		84D2292B28C61C8D00F64FE7 /* WKNavigationPolicyProvider.CustomResponseCard.swift in Sources */ = {isa = PBXBuildFile; fileRef = 84D2292A28C61C8D00F64FE7 /* WKNavigationPolicyProvider.CustomResponseCard.swift */; };
@@ -1115,6 +1116,7 @@
 		8491AF472A94EE8700CC3E72 /* ConfigurationDeeplinkHandlerTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ConfigurationDeeplinkHandlerTests.swift; sourceTree = "<group>"; };
 		8491AF4D2A9CB3A400CC3E72 /* SecureConversations.TranscriptModel+GVA.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "SecureConversations.TranscriptModel+GVA.swift"; sourceTree = "<group>"; };
 		8491AF4F2A9CBB0400CC3E72 /* TranscriptModelTests+GVA.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "TranscriptModelTests+GVA.swift"; sourceTree = "<group>"; };
+		8491AF512A9F813200CC3E72 /* SecureConversations.TranscriptModel.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SecureConversations.TranscriptModel.swift; sourceTree = "<group>"; };
 		84A318A02869ECFC00CA1DE5 /* Unavailable.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Unavailable.swift; sourceTree = "<group>"; };
 		84CFB7722822700000167258 /* Theme.Button.Accessibility.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Theme.Button.Accessibility.swift; sourceTree = "<group>"; };
 		84D2292A28C61C8D00F64FE7 /* WKNavigationPolicyProvider.CustomResponseCard.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = WKNavigationPolicyProvider.CustomResponseCard.swift; sourceTree = "<group>"; };
@@ -2580,6 +2582,7 @@
 				311CAFCC29F8FAE20067B59F /* SecureConversations.TranscriptModel+CustomCard.swift */,
 				8491AF4D2A9CB3A400CC3E72 /* SecureConversations.TranscriptModel+GVA.swift */,
 				31DD41642A57105400F92612 /* SecureConversations.TranscriptModel.Environment.swift */,
+				8491AF512A9F813200CC3E72 /* SecureConversations.TranscriptModel.swift */,
 			);
 			path = ChatTranscript;
 			sourceTree = "<group>";
@@ -4680,6 +4683,7 @@
 				9AB196D627C3E1E400FD60AB /* ChatViewModel.Environment.Interface.swift in Sources */,
 				3197F7B429F7C26A008EE9F7 /* SecureConversations.ChatWithTranscriptViewModel+Hashable.swift in Sources */,
 				AF0D26D82971912A00816CCB /* SecureConversations.SendMessageButton.swift in Sources */,
+				8491AF522A9F813200CC3E72 /* SecureConversations.TranscriptModel.swift in Sources */,
 				1A0C9A8625C4090D00815406 /* CallButton.swift in Sources */,
 				9AB196EA27C5390100FD60AB /* ChatAttachment.Mock.swift in Sources */,
 				75940958298D386F008B173A /* Makeable.swift in Sources */,