feat: invalidate etag on context change

Signed-off-by: Todd Baert <todd.baert@dynatrace.com>

Author: toddbaert

libs/providers/ofrep-web/src/lib/ofrep-web-provider.ts

@@ -133,6 +133,7 @@ export class OFREPWebProvider implements Provider {
    */
   async onContextChange(oldContext: EvaluationContext, newContext: EvaluationContext): Promise<void> {
     try {
+      this._etag = null; // reset etag to force refetch
       this._context = newContext;
 
       const now = new Date();