Provide a reusable device plugin utility for local MCAP recording

Context

While reviewing Jerry's PR (https://github.com/NVIDIA/IsaacTeleop/pull/691), a question came up about whether the plugin binary needs two modes — in particular the local MCAP recording feature alongside the OpenXR push path.
Per discussion, the local MCAP recording was added as a dev convenience: a way to verify the plugin works standalone (e.g. checking OGLO integration) without depending on the full OpenXR push pipeline. For this PR, that local MCAP path will be dropped and only the OpenXR push version kept, to avoid shipping two modes in the plugin binary.

Proposal

The standalone-verification pattern is broadly useful, so rather than baking it into each plugin, we should provide it once as a shared/reusable utility that any plugin can use to confirm it works correctly on its own. This keeps individual plugin binaries lean (single mode) while preserving the local-recording capability for development and debugging.

Motivation

Lets plugin authors sanity-check a plugin in isolation, decoupled from the OpenXR push path.
Avoids each plugin carrying its own dual-mode logic and MCAP-recording code.
Standardizes how we capture/inspect plugin output during development.

Open questions

Where should this live — a shared dev tool/CLI, or a library plugins can opt into?
Scope of MCAP recording: just plugin output, or broader session capture?
Priority — this is a "someday" nice-to-have surfaced from the PR discussion, not a blocker for the current change.

Start by reviewing the local MCAP recording path discussed in PR 691 and how the OpenXR push version separates plugin behavior. Decide whether the reusable utility belongs in a shared dev tool/CLI or an opt-in library, and define whether it records plugin output or broader session data. Done means the scope and priority are resolved well enough to implement a shared standalone-verification utility.