Relationships between each category of 25‐item frailty risk assessment (<scp>K</scp>ihon <scp>C</scp>hecklist) and newly certified older adults under <scp>L</scp>ong‐<scp>T</scp>erm <scp>C</scp>are <scp>I</scp>nsurance: A 24‐month follow‐up study in a rural community in <scp>J</scp>apan