An ornamentaldesign for a ceiling mount sensor, as shown and described.
FIG. 1 is a bottom perspective view of the ceiling mount sensor.
FIG. 2 is a front elevation view thereof.
FIG. 3 is a rear elevation view thereof.
FIG. 4 is a left side elevation view thereof.
FIG. 5 is a right side elevation view thereof; and,
FIG. 6 is a bottom plan view thereof.
The top plan view of the ceiling mount sensor forms no part of the claimed design. The broken lines shown in the drawings depict subject matter that is hereby disclaimed and forms no part of the claimed design.