chore(performance): tweaked thresholds (#1881)

<!--- Provide a general summary of your changes in the Title above -->

## Description

Tweaked thresholds for create dialogs and transmissions

## Related Issue(s)

- #1862 

## Verification

- [ ] **Your** code builds clean without any errors or warnings
- [ ] Manual testing done (required)
- [ ] Relevant automated test added (if you find this hard, leave it and
we'll help out)

## Documentation

- [ ] Documentation is updated (either in `docs`-directory, Altinnpedia
or a separate linked PR in
[altinn-studio-docs.](https://github.com/Altinn/altinn-studio-docs), if
applicable)

tests/k6/tests/serviceowner/performance/createDialogWithThresholds.js

@@ -6,7 +6,7 @@ export let options = {
     vus: 1,
     duration: "30s",
     thresholds: {
-        "http_req_duration{name:create dialog}": ["p(95)<200"],
+        "http_req_duration{name:create dialog}": ["p(95)<300"],
         "http_reqs{name:create dialog}": []   
     }
 }

tests/k6/tests/serviceowner/performance/createTransmissionsWithThresholds.js

@@ -7,9 +7,9 @@ export const options = {
     vus: 1,
     duration: "30s",
     thresholds: {
-        "http_req_duration{name:create dialog}": ["p(95)<200"],
+        "http_req_duration{name:create dialog}": ["p(95)<300"],
         "http_reqs{name:create dialog}": [],
-        "http_req_duration{name:create transmission}": ["p(95)<200"],
+        "http_req_duration{name:create transmission}": ["p(95)<500"],
         "http_reqs{name:create transmission}": []
     }
 };