Rename "Execution Log" to "Execution Details"

[ievdokdm]

Rename "Execution Log" to "Execution Details"
For Successfully executed job add text "[Job Name] Executed Successfully. Click "View more details on LUCI UI" button bellow for more details."
Rename "No log summary available" to "No execution details available"

[wadelhw]

A fix has been proposed in flutter/cocoon#5006. The issue will auto-close when that PR is merged.