Update ETA descriptions to 90 chars limit

From Google : The maximum character count was increased from 80 to 90 for description1 and description2 of ExpandedTextAd, ExpandedDynamicSearchAd, and CallOnlyAd.

Link : https://developers.google.com/adwords/api/docs/reference/release-notes/v201809

For Bing :
https://docs.microsoft.com/en-us/bingads/customer-management-service/getcustomerpilotfeatures?view=bingads-12#featurepilotflags

Looks like we need to ensure that we are a part of pilot 511 to be able to use longer description (ad text)