[feature] Add fields introduced in Mastodon 4.4.0 to `/api/v2/instance` response (#4240)

# Description

## Checklist

- [x] I/we have read the [GoToSocial contribution guidelines](https://codeberg.org/superseriousbusiness/gotosocial/src/branch/main/CONTRIBUTING.md).
- [ ] I/we have discussed the proposed changes already, either in an issue on the repository, or in the Matrix chat.
- [x] I/we have not leveraged AI to create the proposed changes.
- [x] I/we have performed a self-review of added code.
- [x] I/we have written code that is legible and maintainable by others.
- [ ] I/we have commented the added code, particularly in hard-to-understand areas.
- [x] I/we have made any necessary changes to documentation.
- [ ] I/we have added tests that cover new code.
- [ ] I/we have run tests and they pass locally with the changes.
- [x] I/we have run `go fmt ./...` and `golangci-lint run`.

Reviewed-on: https://codeberg.org/superseriousbusiness/gotosocial/pulls/4240
Co-authored-by: nicole mikołajczyk <git@mkljczk.pl>
Co-committed-by: nicole mikołajczyk <git@mkljczk.pl>

1 files changed, 7 insertions, 2 deletions

diff --git a/internal/typeutils/internaltofrontend_test.go b/internal/typeutils/internaltofrontend_test.go
index d19bd6a2f..03d812556 100644
--- a/internal/typeutils/internaltofrontend_test.go
+++ b/internal/typeutils/internaltofrontend_test.go
@@ -2521,7 +2521,10 @@ func (suite *InternalToFrontendTestSuite) TestInstanceV2ToFrontend() {
   ],
   "configuration": {
     "urls": {
-      "streaming": "wss://localhost:8080"
+      "streaming": "wss://localhost:8080",
+      "about": "http://localhost:8080/about",
+      "privacy_policy": null,
+      "terms_of_service": "http://localhost:8080/about#rules"
     },
     "accounts": {
       "allow_custom_css": true,
@@ -2587,7 +2590,9 @@ func (suite *InternalToFrontendTestSuite) TestInstanceV2ToFrontend() {
   "registrations": {
     "enabled": true,
     "approval_required": true,
-    "message": null
+    "message": null,
+    "min_age": null,
+    "reason_required": true
   },
   "contact": {
     "email": "admin@example.org",