`inspect` command does not honour `inputs.d` external input directory

At https://github.com/elastic/elastic-agent/commit/3c2072d8d2fc52d842aa301ab3a4cd1de1eb3710 support for `inputs.d` external input directory was added. However `elastic-agent inspect` command seems to not take into account the `inputs.d ` directory during its execution.

I was checking the code of the command at https://github.com/elastic/elastic-agent/blob/a950518c38ed69b6ce3f7216b79b785079b013b1/internal/pkg/agent/cmd/inspect.go#L286 and it might misses to include the additional configs like it happens at https://github.com/elastic/elastic-agent/blob/07a476d591353f9b20dbe17a9f05ed6353741b33/internal/pkg/agent/application/local_mode.go#L121

Since `inspect` command is really useful for evaluating policies etc it would be nice to provide full access to any additional inputs available.

cc: @kvch