fix(ui): set content-type for certain UI requests (argoproj#16923)

Signed-off-by: Michael Crenshaw <[email protected]>

ui/src/app/shared/services/applications-service.ts

@@ -328,6 +328,7 @@ export class ApplicationsService {
                 kind: resource.kind,
                 group: resource.group
             })
+            .set("Content-Type", "application/json")
             .send(JSON.stringify(action))
             .then(res => (res.body.actions as models.ResourceAction[]) || []);
     }
@@ -345,6 +346,7 @@ export class ApplicationsService {
                 group: resource.group || '', // The group query param must be present even if empty.
                 patchType
             })
+            .set("Content-Type", "application/json")
             .send(JSON.stringify(patch))
             .then(res => res.body as {manifest: string})
             .then(res => JSON.parse(res.manifest) as models.State);
@@ -364,6 +366,7 @@ export class ApplicationsService {
                 force,
                 orphan
             })
+            .set('Content-Type', 'application/json')
             .send()
             .then(() => true);
     }