Fix laser scan matcher tf2 lookup warning

With the noetic version of the laser_scan_matcher_node (used in the
stretch_scan_matcher.launch file), an undocumented parameter `use_tf`
was added to the node. This parameter defaults to true, and drives
a newer motion model for the node where the fixed frame (odom) ->
base_link TF is looked up to retrieve the previous motion step
estimate. Then, this prev motion step is used to inform the next
motion step. I don't know why the node looks up the previous motion
step via TF, when it should already know it (it published it!).
Anyways, this TF lookup fails and warns:

[ WARN] [1704785850.605420614]: Could not get base to fixed frame
transform, Lookup would require extrapolation 0.134955875s into the
future.  Requested time 1704785850.369850636 but the latest data is
at time 1704785850.234894753, when looking up transform from frame
[base_link] to frame [odom]

Since this tf lookup is failing and the use_tf motion model isn't
working, this commit disables the motion model by setting the
use_tf flag to false.

stretch_core/launch/stretch_scan_matcher.launch

@@ -16,6 +16,7 @@
     <param name="max_linear_correction" value="0.2"/>
 
     <param name="use_imu" value="false"/>
+    <param name="use_tf" value="false"/>
 
   </node>
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