[BUG]: RawValue no longer supports mysql functions

[ALameLlama]

Describe the bug
It looks like the change in this PR #15413 has broken how it handles MySQL functions

To Reproduce
This is taken from the function example Docblock.
$subscriber->createdAt = new \Phalcon\Db\RawValue("now()");
Or something like:
$subscriber->expiry = new \Phalcon\Db\RawValue("now() + INTERVAL 30 DAY");

PDOException #22007
SQLSTATE[22007]: Invalid datetime format: 1292 Incorrect datetime value: 'now()' for column `database`.`table`.`created_at` at row 1
PDOException #22007
SQLSTATE[22007]: Invalid datetime format: 1292 Incorrect datetime value: 'now() + INTERVAL 30 DAY' for column `database`.`table`.`expiry` at row 1

Details

• Phalcon version: 5.0.0RC3
• PHP Version: 7.4.30
• Operating System: Ubuntu 20.04.4
• Installation type: Any
• Zephir version (if any): NA
• Server: Apache

[niden]

Resolved in #16038