Disables rate limit for headless app (#3219)

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For some simple cases, disabling rate limit in the runloop can help
improve performance in headless mode.
Follow PR to https://github.com/isaac-sim/IsaacLab/pull/3089, which only
updated it for rendering headless app.
However, this also impacts non-rendering workflows, so adding it to the
default headless app as well.

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## Type of change

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- Bug fix (non-breaking change which fixes an issue)


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---------
Signed-off-by: matthewtrepte <mtrepte@nvidia.com>

apps/isaaclab.python.headless.kit

@@ -88,6 +88,9 @@ app.audio.enabled = false
 # Enable Vulkan - avoids torch+cu12 error on windows
 app.vulkan = true
 
+# Disables rate limit in runloop
+app.runLoops.main.rateLimitEnabled=false
+
 # hide NonToggleable Exts
 exts."omni.kit.window.extensions".hideNonToggleableExts = true
 exts."omni.kit.window.extensions".showFeatureOnly = false