uses: properly handle recursive deps exceptions

Fixes #1776.

If any known formula had a dependency on an untapped tap,
Formula#recursive_dependencies would throw an exception, which would be
caught by the outer exception handler, causing the rest of the
dependencies for that formula to be skipped and incomplete output to be
generated.

To fix this, I added a check to avoid analysing the dependencies of
formulae from uninstalled taps.

Additionally, I removed the aforementioned outer exception handler added
in 5fdb89aed90f03413cdb21af430411c4a722876e, because the only other
place that should be capable of throwing such an exception is the
statement that was surrounded by another wider exception handler in
Homebrew/legacy-homebrew#40682.

Library/Homebrew/cmd/uses.rb

@@ -47,7 +47,6 @@ module Homebrew
 
     uses = formulae.select do |f|
       used_formulae.all? do |ff|
-        begin
         if recursive
           deps = f.recursive_dependencies do |dependent, dep|
             if dep.recommended?
@@ -57,6 +56,12 @@ module Homebrew
             elsif dep.build?
               Dependency.prune unless includes.include?("build?")
             end
+
+            # If a tap isn't installed, we can't find the dependencies of one
+            # its formulae, and an exception will be thrown if we try.
+            if dep.is_a?(TapDependency) && !dep.tap.installed?
+              Dependency.keep_but_prune_recursive_deps
+            end
           end
           reqs = f.recursive_requirements do |dependent, req|
             if req.recommended?
@@ -86,10 +91,6 @@ module Homebrew
         reqs.any? do |req|
           req.name == ff.name || [ff.name, ff.full_name].include?(req.default_formula)
         end
-        rescue FormulaUnavailableError
-          # Silently ignore this case as we don't care about things used in
-          # taps that aren't currently tapped.
-        end
       end
     end