Bluetooth: Mesh: Fix Heartbeat Pub/Sub Count/Period Log calculation

Mesh Profile Specification Errata 11737 specifies that
Period/Count Log value 0x11 is not defined Log field
transformation in Table 4.1.

Errata 11737 adds value 0x11 to Log field transformation
table with 2-octet value equal to 0x10000 which does not fit into
two octets. This patch changes period calculation to 32-bit precision.
There is also a special case for publication count. If the
log value is equal to 0x11 then the publication count value
should be 0xfffe. When sending Hearbeat Publication Status
message we should return the same value as the one received
in Publication Set so we have to add a case in hb_pub_count_log().

Co-authored-by: Alperen Sener <alperen.sener@nordicsemi.no>
Signed-off-by: Michał Narajowski <michal.narajowski@codecoup.pl>
Signed-off-by: Pavel Vasilyev <pavel.vasilyev@nordicsemi.no>