Fix detection of string interpolation

- This was almost there but not quite and the lack of tests lulled me into a false sense of security.

Library/Homebrew/rubocops/cask/no_overrides.rb

@@ -44,8 +44,8 @@ module RuboCop
                 next if send_node.method_name == :livecheck
                 next if send_node.parent.block_type? && send_node.parent.method_name == :livecheck
 
-                # Skip string interpolations (`:begin` inside `:dstr`).
-                next if send_node.begin_type? && send_node.parent_node.dstr_type?
+                # Skip string interpolations (`:send` inside `:begin` inside `:dstr`).
+                next if send_node.parent.begin_type? && send_node.parent.parent.dstr_type?
                 next if ON_SYSTEM_METHODS.include?(send_node.method_name)
 
                 names.add(send_node.method_name)

Library/Homebrew/test/rubocops/cask/no_overrides_spec.rb

@@ -43,7 +43,7 @@ describe RuboCop::Cop::Cask::NoOverrides do
       <<~CASK
         cask 'foo' do
           arch arm: "arm64", intel: "x86"
-          version = '1.2.3'
+          version '1.2.3'
           on_mojave :or_later do
             url "https://brew.sh/foo-\#{version}-\#{arch}.pkg"
           end