Led dimming circuit is not able to switch off the led
The datasheet in section 8.3.11 PWM (UVLO and Enable) says

Because
the PWM
pin is also UVLO
(undervoltage
lockout
and device
enable),
when
pulled
low it is necessary
to ensure
the output
is 100%
OFF.
The high-side
FET
driver
has a small
leakage
path
to the output.
Although
very
small
(&lt;&lt;100
μ
A), theLEDs
could
glow
if the current
was not eliminated.
The 100-
μ
A (typical)
pulldown
is activated
and
held ON while
PWM
is low and ensures
no light output

so disable the driver when you want to turn it off by pulling the PWM pin low from your micro.