formula_installer: handle attempts to load invalid casks

Certain casks in the main cask repository may be invalid, for whatever
reason. Without handling this exception, the user will get a cask-related
exception while the formula of the same name is installed, and their
installation will abort half-completed.

Fixes #5709.

Library/Homebrew/formula_installer.rb

@@ -790,7 +790,7 @@ class FormulaInstaller
 
     cask_installed_with_formula_name = begin
       Cask::CaskLoader.load(formula.name).installed?
-    rescue Cask::CaskUnavailableError
+    rescue Cask::CaskUnavailableError, Cask::CaskInvalidError
       false
     end