RuboCop: Enable previously disabled cops for Capybara/* and Naming/*

What does this MR do and why?

This MR enables the following 👮 rules which were disabled only due to too many offenses:

• Capybara/VisibilityMatcher
• Naming/HeredocDelimiterNaming
• Naming/RescuedExceptionsVariableName

All pending TODOs have been regenerated via

rake 'rubocop:todo:generate[
  Capybara/VisibilityMatcher,
  Naming/HeredocDelimiterNaming,
  Naming/RescuedExceptionsVariableName
]'

How to set up and validate locally

rake 'rubocop:todo:generate[
  Capybara/VisibilityMatcher,
  Naming/HeredocDelimiterNaming,
  Naming/RescuedExceptionsVariableName
]'

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.