[chore] Upgrade to Go 1.24 (#4187)

* Set `go.mod` to 1.24 now that it's been out for 3 months.
* Update all the test to use `testing.T.Context()`.

Reviewed-on: https://codeberg.org/superseriousbusiness/gotosocial/pulls/4187
Co-authored-by: Daenney <git@noreply.sourcery.dny.nu>
Co-committed-by: Daenney <git@noreply.sourcery.dny.nu>

internal/api/client/lists/listaccountsadd_test.go

@@ -19,7 +19,6 @@ package lists_test
 
 import (
 	"bytes"
-	"context"
 	"fmt"
 	"io"
 	"net/http"
@@ -106,7 +105,7 @@ func (suite *ListAccountsAddTestSuite) TestPostListAccountOK() {
 
 	// Remove turtle from the list.
 	if err := suite.db.DeleteListEntry(
-		context.Background(),
+		suite.T().Context(),
 		entry.ListID,
 		entry.FollowID,
 	); err != nil {