Fix data type when querying remote_dev type

The check of BT_PROPERTY_TYPE_OF_DEVICE property requires size of 4
bytes, but some of the read attempts only provide 1 byte of data.
This causes those read attempts to fail.

Even though the underlying data fits within 1 byte, there are a lot
of places which assume 4 bytes of data, so changing this to 1 byte
breaks those assumption and might introduce unwanted side effects.

This CL modifies those failed reads to provide exactly 4 bytes.
Additionally, this also replaces every accessors that uses enum to use
uint32_t instead, since enum size is not guaranteed to be 4 bytes.

Bug: 300418914
Tag: #floss
Test: m -j
Test: Manually, make sure we don't fail reading dev_type from storage
      by adding logs and just scan some advertisements.

Change-Id: Ie2a880813ed5e4666813e02bb6914ae52950bb09