[SysUI][Floaty] Fix incorrect default value picked for LPP setting

Fetching POWER_BUTTON_LONG_PRESS's value using GlobalSetting's getInt()
API currently uses "R.integer.config_longPressOnPowerBehavior" directly.
This causes it to return config's resource id instead of the actual
integer value of the config. On further analysis, logs suggest that
POWER_BUTTON_LONG_PRESS setting isn't present and even in
PhoneWindowManager's usage, default value read from config is returned
on the first time.

This change fixes this issue by fetching the actual integer value of the
config.

Test: NONE checked manually by logging value

1. Factory reset the device
2. Add logs in SqueezeEffectRepositoryImpl and PhoneWindowManager to
   print POWER_BUTTON_LONG_PRESS's value using both Settings and
   GlobalSettings API
3. In the logs keep -1 as the default value in API's default param
4. Repeat #3, but this time keep the default value as the integer value
   of the config "R.integer.config_longPressOnPowerBehavior"
5. In both #3 and #4, logs coming from both files should point to
   exactly same values
6. Repeat #1 to #5 couple times and ensure that #5 is correct everytime

Flag: com.android.systemui.shared.enable_lpp_assist_invocation_effect
Bug: 399263897

Change-Id: Ifbe7f8fe66dc6fe67a98f5c375668e9342c31204