Enforce minimum of 32 bit flags length

[dwelch-r7]

Currrently during conversion from ccache to kirbi formats the flags field can come out as less than the 32 bits specified by the spec, this PR forces that it's a minimum of 32 bits https://datatracker.ietf.org/doc/html/rfc4120#section-5.2.8

KerberosFlags ::= BIT STRING (SIZE (32..MAX)) -- minimum number of bits shall be sent, -- but no fewer than 32