feat(eventstore): accept transaction in push (#8945)

# Which Problems Are Solved

Push is not capable of external transactions.

# How the Problems Are Solved

A new function `PushWithClient` is added to the eventstore framework
which allows to pass a client which can either be a `*sql.Client` or
`*sql.Tx` and is used during push.

# Additional Changes

Added interfaces to database package.

# Additional Context

- part of https://github.com/zitadel/zitadel/issues/8931

---------

Co-authored-by: Livio Spring <livio.a@gmail.com>
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

internal/eventstore/eventstore_test.go

@@ -330,6 +330,12 @@ func Test_eventData(t *testing.T) {
 	}
 }
 
+var _ Pusher = (*testPusher)(nil)
+
+func (repo *testPusher) Client() *database.DB {
+	return nil
+}
+
 type testPusher struct {
 	events []Event
 	errs   []error
@@ -341,7 +347,7 @@ func (repo *testPusher) Health(ctx context.Context) error {
 	return nil
 }
 
-func (repo *testPusher) Push(ctx context.Context, commands ...Command) (events []Event, err error) {
+func (repo *testPusher) Push(_ context.Context, _ database.QueryExecuter, commands ...Command) (events []Event, err error) {
 	if len(repo.errs) != 0 {
 		err, repo.errs = repo.errs[0], repo.errs[1:]
 		return nil, err