Provide support for "Avg. Page Load Time" metric in LookerStudio Connector

[goochj03]

Currently the Actions > Page URLs report when loaded via the Matomo LookerStudio connector displays a metric of "Avg Generation Time". This metric appears to be deprecated and returns no data.

The Behaviour > Pages report in the Matomo UI and API provides "Avg. Page Load Time" if this metric can be available via the LookerStudio connector this would help customers wanting to replicate this report.