[TRACKING] Agency Card flow improvements

[angela-tran]

Based on design specs in #1907

Acceptance criteria

• Eligibility index: update copy to be more consistent and provide context for user #2007
• Eligibility start: update copy to be more consistent  #2010
• Eligibility confirm: make copy more specific, and improve field helper text #2011
• Form field validation: update copy to be more specific on the problem #2012
• New screen Eligibility error for Agency Card flow only #2013
• Enrollment index: update copy to more clearly call out that contactless card is used for enrollment #2014
• Fix default enrollment index copy, override for Agency cards #2073
• Enrollment success: update copy and spacing #2015
• Translate all strings for Improved UX for agency card enrollment #2075
• QA Spanish copy on test-benefits.calitp.org for Improved UX for agency card enrollment #2076