[NO-TICKET] Disable Dir interruption bug workaround on Ruby 3.4+

**What does this PR do?**

This PR disables the Dir interruption bug workaround that was added in
 #3720 for Ruby versions 3.4 and above.

**Motivation:**

The bug has been fixed upstream (see
https://bugs.ruby-lang.org/issues/20586 ) and thus is no longer needed!

**Additional Notes:**

N/A

**How to test the change?**

This change includes test coverage.

lib/datadog/core/configuration/settings.rb

@@ -410,10 +410,8 @@ def initialize(*_)
             # The profiler gathers data by sending `SIGPROF` unix signals to Ruby application threads.
             #
             # We've discovered that this can trigger a bug in a number of Ruby APIs in the `Dir` class, as
-            # described in https://github.com/DataDog/dd-trace-rb/issues/3450 . This workaround prevents the issue
-            # from happening by monkey patching the affected APIs.
-            #
-            # (In the future, once a fix lands upstream, we'll disable this workaround for Rubies that don't need it)
+            # described in https://bugs.ruby-lang.org/issues/20586 .
+            # This was fixed for Ruby 3.4+, and this setting is a no-op for those versions.
             #
             # @default `DD_PROFILING_DIR_INTERRUPTION_WORKAROUND_ENABLED` environment variable as a boolean,
             # otherwise `true`

lib/datadog/profiling/component.rb

@@ -435,10 +435,7 @@ def self.build_profiler_component(settings:, agent_settings:, optional_tracer:)
       end
 
       private_class_method def self.dir_interruption_workaround_enabled?(settings, no_signals_workaround_enabled)
-        return false if no_signals_workaround_enabled
-
-        # NOTE: In the future this method will evolve to check for Ruby versions affected and not apply the workaround
-        # when it's not needed but currently all known Ruby versions are affected.
+        return false if no_signals_workaround_enabled || RUBY_VERSION >= "3.4"
 
         settings.profiling.advanced.dir_interruption_workaround_enabled
       end

spec/datadog/profiling/component_spec.rb

@@ -543,13 +543,27 @@
         let(:no_signals_workaround_enabled) { false }
 
         before do
-          expect(described_class).to receive(:no_signals_workaround_enabled?).and_return(no_signals_workaround_enabled)
+          allow(described_class).to receive(:no_signals_workaround_enabled?).and_return(no_signals_workaround_enabled)
         end
 
-        it "is enabled by default" do
-          expect(Datadog::Profiling::Ext::DirMonkeyPatches).to receive(:apply!)
+        context "on Ruby >= 3.4" do
+          before { skip "Behavior does not apply to current Ruby version" if RUBY_VERSION < "3.4." }
 
-          build_profiler_component
+          it "is never applied" do
+            expect(Datadog::Profiling::Ext::DirMonkeyPatches).to_not receive(:apply!)
+
+            build_profiler_component
+          end
+        end
+
+        context "on Ruby < 3.4" do
+          before { skip "Behavior does not apply to current Ruby version" if RUBY_VERSION >= "3.4." }
+
+          it "is applied by default" do
+            expect(Datadog::Profiling::Ext::DirMonkeyPatches).to receive(:apply!)
+
+            build_profiler_component
+          end
         end
 
         context "when the no signals workaround is enabled" do