"Lock pages in memory" is not a requirement for Spotlight service account.
If you find that the "Lock pages in memory" is enabled for the Spotlight service account, it is not done by Spotlight.
No where in the installation of Spotlight and no where in the use of Spotlight will Spotlight cause the "Lock pages in memory" to be enabled for the service account associated with Spotlight.
Also, Spotlight does not create the service account during install or any time during use. The service account associated with Spotlight is any existing Active Directory account the end user chooses to use with Spotlight.
As Spotlight does not require this right, you may remove the service account entry from "Lock pages in memory" by going to Computer Configuration -> Windows Settings -> Security Settings -> Local Policies -> User Rights Assignment -> "Lock pages in memory".