Add isConnected method to encoders

[rcahoon]

Description

isConnected() should return true iff the software is receiving up-to-date and correct information from the encoder. This is primarily useful with the Rev absolute encoders, but also is applicable to CANcoders.

example use:

2025/src/main/java/com/team766/robot/burro_arm/mechanisms/Arm.java

Lines 51 to 62 in 1060e1c

	if (!initialized && absoluteEncoder.isConnected()) {
	final double absoluteEncoderPosition =
	Math.IEEEremainder(
	absoluteEncoder.getPosition() + absoluteEncoderOffset.get(), 1.0);
	SmartDashboard.putNumber(
	"[ARM] AbsoluteEncoder Init Position", absoluteEncoderPosition);
	motor.setSensorPosition(
	absoluteEncoderPosition
	* ABSOLUTE_ENCODER_TO_ARM_ANGLE
	/ MOTOR_ROTATIONS_TO_ARM_ANGLE);
	initialized = true;
	}

Original 2024 PRs: Team766/2024#137 Team766/2024#94

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Be detailed so that your code reviewer can understand exactly how much and what kinds of testing were done, and which might still be worthwhile to do.

• Unit tests: [Add your description here]
• Simulator testing: [Add your description here]
• On-robot bench testing: Tested on m-ayhem demo bot
• On-robot field testing: [Add your description here]