Object inspection doesn't work inside Mocks that doesn't expect the `singleton_class` method called

[decheverria1]

Your environment

• ruby -v: ruby 3.3.7 (2025-01-15 revision be31f993d7) [x86_64-linux]
• rdbg -v: rdbg 1.11.0

Describe the bug
Object inspection doesn't work inside Mocks that doesn't expect the singleton_class method called
unmocked method :singleton_class

To Reproduce
You can try to reproduce it using a minitest Mock

mock = Minitest::Mock.new

mock.expect :call, true do |*passed_args, **passed_kwargs|
 debugger
end

mock.call(123)

Or make your own mock class from scratch (of course is not the same as minitest but mimics it)

class Mock
 def initialize
 @expected = {}
 end

 def expect(name, return_value = nil, expected_args = nil, &block)
 @expected[name.to_sym] = [return_value, expected_args, block]
 self
 end

 def method_missing(name, *args, **kwargs, &blk)
 entry = @expected[name.to_sym]
 raise NoMethodError, "unmocked method #{name.inspect}, expected one of #{@expected.keys.inspect}" unless entry

 return_value , expected_args, stored_block = entry
 return stored_block.call(*args, **kwargs) if stored_block
 return_value 
 end

 def respond_to_missing?(name, include_private = false)
 @expected.key?(name.to_sym) || super
 end

 def singleton_class
 method_missing(:singleton_class)
 end
end

mock = Mock.new

mock.expect :call, true do |*passed_args, **passed_kwargs|
 debugger
end

mock.call(123)

Expected behavior
It should stop at the debugger, instead we get an error ``full_message': unmocked method :singleton_class, expected one of [:call] (NoMethodError)`

Additional context
I don't really know if this is a problem of MiniTest or from this gem, but binding.pry does not seem to fall into this error. Additionally i have identified that the code dies at lib/debug/frame_info.rb:172 where NoMethodError is not captured, although after inside safe_ispect it is captured, i don't really understand the flow of the gem but maybe we can skip the NoMethodError before safe inspecting. Lastly, i was eager to do a PR but i can't test because i'm on wsl2 and have no fast way of switching to linux at the moment.