[com_actionlogs][3.9]Apply timezone to datetime in com_actionlogs emails

[PhilETaylor]

Steps to reproduce the issue

Closes #22711

Enable the sending of Action Log entries to a Super Admin by Mail in Joomla 3.9
Set your Joomla Global Timezone to be something the other side of the world
Generate a load of emails

Expected result

Any reference to the date/time an event occured should be translated to the Joomla Global Configuration Timezone/offset

Actual result

The date/time right now is UTC/GMT, but a Joomla Super Admin the other side of the world (with a server another third of the way around the world) is confused and assumes its local time, so would be best when giving the date/time to tell the recipient WHAT timezone that timestamp relates to.

[laoneo]

This is actually sent in the timezone of the current logged in user. If the recipient is in a different timezone then the date is wrong.

[mbabker]

This is actually sent in the timezone of the current logged in user. If the recipient is in a different timezone then the date is wrong.

Changed this to:

• Hardcode the time format (so the email doesn't have a different format based on the active user)
• Hardcode the date/time string to UTC

Good to go here, please test