Remote Config package on updating from 1.0.9 to 1.2.1, 1.2.2 or 1.2.3 throws ArgumentNull exceptions and displays a blank window. Refer the attached video

Steps to reproduce:
1) Create a new project
2) Window > Package Manager > Install Remote Config 1.0.9
3) Update Remote Config to 1.2.3

Actual result: ArgumentNull exceptions are thrown and Remote Config displays a blank window on opening

Expected result: No errors are thrown and Remote Config windows works properly

Occurring on: 2020.2.0a1, 2020.2.0a17, 2020.1.0a1, 2020.1.0b16 and 2019.4.2f1 with Remote Config package version 1.2.3, 1.2.2, 1.2.1

Working fine in: 2020.2.0a1, 2020.2.0a17, 2020.1.0a1, 2020.1.0b16 and 2019.4.2f1 with Remote Config package version 1.0.9

Environment: Windows and Mac

Stack trace:
1) ArgumentNullException: Value cannot be null.
Parameter name: input
System.Text.RegularExpressions.Regex.Replace (System.String input, System.String replacement) (at <525dc68fbe6640f483d9939a51075a29>:0)
System.Text.RegularExpressions.Regex.Replace (System.String input, System.String pattern, System.String replacement, System.Text.RegularExpressions.RegexOptions options, System.TimeSpan matchTimeout) (at <525dc68fbe6640f483d9939a51075a29>:0)
System.Text.RegularExpressions.Regex.Replace (System.String input, System.String pattern, System.String replacement) (at <525dc68fbe6640f483d9939a51075a29>:0)
Unity.RemoteConfig.Editor.RemoteConfigWindow.DrawEnvironmentDropdown (System.Single currentY) (at Library/PackageCache/com.unity.remote-config@1.2.3/Editor/RemoteConfigWindow.cs:617)
Unity.RemoteConfig.Editor.RemoteConfigWindow.DrawToolbar (UnityEngine.Rect toolbarSize) (at Library/PackageCache/com.unity.remote-config@1.2.3/Editor/RemoteConfigWindow.cs:300)
Unity.RemoteConfig.Editor.RemoteConfigWindow.OnGUI () (at Library/PackageCache/com.unity.remote-config@1.2.3/Editor/RemoteConfigWindow.cs:218)
UnityEditor.HostView.InvokeOnGUI (UnityEngine.Rect onGUIPosition, UnityEngine.Rect viewRect) (at <d837524d64254fc683935c524089cd1c>:0)
UnityEditor.DockArea.DrawView (UnityEngine.Rect viewRect, UnityEngine.Rect dockAreaRect) (at <d837524d64254fc683935c524089cd1c>:0)
UnityEditor.DockArea.OldOnGUI () (at <d837524d64254fc683935c524089cd1c>:0)
UnityEngine.UIElements.IMGUIContainer.DoOnGUI (UnityEngine.Event evt, UnityEngine.Matrix4x4 parentTransform, UnityEngine.Rect clippingRect, System.Boolean isComputingLayout, UnityEngine.Rect layoutSize, System.Action onGUIHandler, System.Boolean canAffectFocus) (at <a332e9421e0b44d18574a55c396a594f>:0)
UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr, Boolean&)