Fix handling of focus charges

[TeamRocketElite]

Under current behavior, the Focus Charge lights go out if an off focus 5 Star Hero is pulled before all 3 Focus Charge lights have lit up. This behavior is incorrect.

The correct behavior is described in the Focus Charge documentation:
https://new-guide.fire-emblem-heroes.com/en-US/feh-3760.html

"The charges will automatically reset if you summon a 5[*] focus Hero while all three charges are active"

The key point is all 3 charges must be lit before they will reset.

This commit changes the behavior of the simulator to match the documentation which is the same as the in game behavior. Focus Charges will not reset if a 5* Hero is pulled before all 3 charges are lit.

[DTM9025]

I saw this and I got really curious on a lot of the edge cases regarding focus charges, specifically on a situation where you enter into a summoning session with 2 charges, reveal a stone and got a nonfocus 5* thus getting 3 charges, and then revealing another stone and immediately getting a focus 5*. I wondered if that situation made it so when you exit the session you no longer got the focus charge effect active.

After doing a bit of digging, it appears the implementation is the simplest. The focus charge effect is only active on the next session, and thus the above scenario of fulfilling the 3 charges and then getting a focus 5* would not remove your focus charges as the effect hasn't activated yet. Specifically, the notification says the following:

Even if you summon additional 5★ Heroes after all three charges are already lit, additional charges will not be lit.

Also, if you summon a 5★ focus Hero when you only have one or two charges lit, those charges will not go out.

If you get all three charges lit and then immediately summon a 5★ focus Hero without exiting the summoning session, all three charges will remain lit. If you exit the summoning screen and start a new summoning session, all three charges will be lit and the Focus Charge effect will be in effect.

Once the Focus Charge effect is active, the charges will not go out even if you summon a 5★ focus Hero for free after summoning 40 or more times in the summoning event.

What does this mean for this commit? Well nothing. This commit will perfectly do the correct behavior as the code to get rid of the focus charges happens before focus charges are added. Just wanted to have some documentation in case someone brings it up.