[bugfix] return 422 for invalid status visibility (#4252)

Signed-off-by: nicole mikołajczyk <git@mkljczk.pl>

# Description

closes #4247

## Checklist

Please put an x inside each checkbox to indicate that you've read and followed it: `[ ]` -> `[x]`

If this is a documentation change, only the first checkbox must be filled (you can delete the others if you want).

- [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.
- [ ] I/we have made any necessary changes to documentation.
- [x] I/we have added tests that cover new code.
- [x] 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/4252
Co-authored-by: nicole mikołajczyk <git@mkljczk.pl>
Co-committed-by: nicole mikołajczyk <git@mkljczk.pl>

internal/processing/status/create_test.go

@@ -18,6 +18,7 @@
 package status_test
 
 import (
+	"net/http"
 	"testing"
 
 	apimodel "code.superseriousbusiness.org/gotosocial/internal/api/model"
@@ -240,6 +241,31 @@ func (suite *StatusCreateTestSuite) TestProcessNoContentTypeUsesDefault() {
 	suite.Equal(apimodel.StatusContentTypeDefault, apiStatus.ContentType)
 }
 
+func (suite *StatusCreateTestSuite) TestProcessInvalidVisibility() {
+	ctx := suite.T().Context()
+	creatingAccount := suite.testAccounts["local_account_1"]
+	creatingApplication := suite.testApplications["application_1"]
+
+	statusCreateForm := &apimodel.StatusCreateRequest{
+		Status:      "my tests content is boring",
+		SpoilerText: "",
+		MediaIDs:    []string{},
+		Poll:        nil,
+		InReplyToID: "",
+		Sensitive:   false,
+		Visibility:  "local",
+		LocalOnly:   util.Ptr(false),
+		ScheduledAt: nil,
+		Language:    "en",
+		ContentType: apimodel.StatusContentTypePlain,
+	}
+
+	apiStatus, errWithCode := suite.status.Create(ctx, creatingAccount, creatingApplication, statusCreateForm)
+	suite.Nil(apiStatus)
+	suite.Equal(http.StatusUnprocessableEntity, errWithCode.Code())
+	suite.Equal("Unprocessable Entity: processVisibility: invalid visibility", errWithCode.Safe())
+}
+
 func TestStatusCreateTestSuite(t *testing.T) {
 	suite.Run(t, new(StatusCreateTestSuite))
 }