Fix getHalVersion overriding UNSUPPORTED version

Setting up mock modem wipes out UNSUPPORTED setting (in case device
is e.g. data-only, so doesn't have IRadioVoice). After restoring
non-mock modem, the setting stays UNKNOWN and never gets restored.
This breaks some CtsTelephonyTestCases tests ran after
TelephonyManagerTestOnMockModem.

This gets fixed by additional isRadioServiceSupported check in
getRadioServiceProxy, but while I was debugging this issue, I also
noticed mHalVersion hits incorrect intermediary steps, e.g.
UNSUPPORTED -> 1_6 -> 1_5 -> 1_4 -> "IRadio <1.4 is no longer
supported." error -> UNKNOWN. I fixed these by checking both upper
and lower bounds of HalVersion (added `between` method).

At last, I extended HalVersion toString with human-readable magic
versions UNSUPPORTED and UNKNOWN.

Bug: 353979854
Test: atest CtsTelephonyTestCases
Flag: EXEMPT bugfix
Change-Id: I7b49dc1cb677acf386d941cb3533ad1ec5c2ff1b