Fix incompatible addon version activation when Bundler.setup fails after retry

When Bundler.setup raises GemNotFound or GitError and the retry has
already been attempted (or install_error is set), the rescue block fell
through without setting setup_error. This caused the server to boot
thinking setup succeeded, bypassing the load_addons guard. Without
Bundler constraining Gem.find_files, every installed version of every
addon gem was discovered, leading to version mismatches
(e.g., ruby-lsp-rails 0.4.2 loaded with ruby-lsp 0.26.5) and ArgumentError
crashes.

The StandardError rescue already handled this correctly - this aligns
the GemNotFound/GitError rescue to do the same.

Author: KaanOzkan

exe/ruby-lsp-launcher

@@ -101,7 +101,7 @@ begin
     Bundler.setup
     $stderr.puts("Composed Bundle set up successfully")
   end
-rescue Bundler::GemNotFound, Bundler::GitError
+rescue Bundler::GemNotFound, Bundler::GitError => e
   # Sometimes, we successfully set up the bundle, but users either change their Gemfile or uninstall gems from an
   # external process. If there's no install error, but the gem is still not found, then we need to attempt to start from
   # scratch
@@ -113,6 +113,10 @@ rescue Bundler::GemNotFound, Bundler::GitError
       exec(Gem.ruby, __FILE__, *ARGV, "--retry")
     end
   end
+
+  setup_error = e
+  $stderr.puts("Failed to set up composed Bundle\n#{e.full_message}")
+  $LOAD_PATH.unshift(File.expand_path("../lib", __dir__))
 rescue StandardError => e
   setup_error = e
   $stderr.puts("Failed to set up composed Bundle\n#{e.full_message}")