Ensure clearCustomConfigurations() is called when changing the configurationProvider (#3404)

* Ensure clearCustomConfigurations() is called when changing the configurationProvider

Author: Colengms

Extension/src/LanguageServer/client.ts

@@ -1206,6 +1206,9 @@ class DefaultClient implements Client {
         }).then(() => {
             let newProvider: string = this.configuration.CurrentConfigurationProvider;
             if (this.configurationProvider !== newProvider) {
+                if (this.configurationProvider) {
+                    this.clearCustomConfigurations();
+                }
                 this.configurationProvider = newProvider;
                 this.updateCustomConfigurations();
                 this.updateCustomBrowseConfiguration();