[TF2] Fix a crash with the Reflect power-up vs the Reflect power-up

[mtxfellen]

Currently in CTFPlayer::OnTakeDamage_Alive, this safeguard exists to prevent a stack overflow whenever a reflected damage instance occurs against a player who themselves is also holding a Reflect power-up.

// Don't recieve reflected damage if you are carrying Reflect (prevents a loop in a game with two Reflect players)
if ( ( info.GetDamageType() & TF_DMG_CUSTOM_RUNE_REFLECT ) && m_Shared.GetCarryingRuneType() == RUNE_REFLECT )
{
	return 0;
}

The game will still crash when two players with Reflect power-ups attack each other, however, due to two issues:

• info.GetDamageType() is checked for TF_DMG_CUSTOM_RUNE_REFLECT, when info.GetDamageCustom() should be checked instead.
• This test is done in CTFPlayer::OnTakeDamage_Alive, but new reflected damage instances are created before that function call is reached in CTFPlayer::OnTakeDamage, meaning the stack overflows before this safeguard is ever reached.

This PR addresses both of the above issues by rectifying the conditional and moving the safeguard to a more appropriate location.