Uncap maxAllowedDataMode in PhoneInfo#RadioInfo

Currently, within PhoneInfo test app, we have an option to override
data mode. It works based on CarrierConfig override. Now, as we
introduce maxAllowedDataMode, CarrierConfig changes to override
data mode is capped within maxAllowedDataMode value. Therefore,
we are making a change to uncap maxAllowedDataMode, so that we are
free to test any data mode through PhoneInfo#RadioInfo.

Bug: 417330132
Test: atest frameworks/opt/telephony/tests/telephonytests/src/com/android/internal/telephony/configupdate/TelephonyConfigUpdateInstallReceiverTest.java
Also, manually tested from PhoneInfo UX
Flag: EXEMPT bug fix

Change-Id: I739af9d69dcaf9954661dd88aa5747cacf370faf