This PR does two things. First, it reduces the verbosity in the customer_testing shard. We want to be less verbose because it's nigh on impossible to find anything when there's a failure in the verbose logs. Also, some additional comments are added to make following the breadcrumbs easier for the next person.
Second, it reverts a timeout that had been set to 90 minutes a while ago. It's no longer needed.
Fixes https://github.com/flutter/flutter/issues/120901.
* Use `dart __deprecated_pub` instead of `pub` to invoke pub from tools
The top level `pub` commmand has been deprecated and will print
a message. It is however implemented via the __deprecated_pub command
that prints no message.
