docs(board): stream_ticks method should be awaited to return TickStream iterator

[HipsterBrown]

The current example usage doc comment for the stream_ticks method demonstrates using an async for loop to process the stream of digital interrupt ticks without awaiting the method call, which is required to fulfill the coroutine and access the TickStream response.

[github-actions]

Warning your change may break code samples. If your change modifies any of the following functions please contact @viamrobotics/fleet-management. Thanks!

component	function
base	is_moving
board	gpio_pin_by_name
camera	get_image
encoder	get_position
motor	is_moving
sensor	get_readings
servo	get_position
arm	get_end_position
gantry	get_lengths
gripper	is_moving
movement_sensor	get_linear_acceleration
input_controller	get_controls
audio	get_properties
pose_tracker	get_poses
power_sensor	get_power
motion	get_pose
vision	get_properties
mlmodel	metadata
slam	get_point_cloud_map