[TF2] fix (most) shield charge prediction errors

[claiwe]

Description

This PR fixes the prediction errors generated for shield charge meters caused by the client not applying the TF_COND_SHIELD_CHARGE condition (and thus the charge meter being off by a few ticks).

[wgetJane]

haven't tested this yet, but i think this'd only fix prediction for when you begin the charge

afaik these are the parts of demoknight shield charging that's unpredicted: - starting the charge (you will suddenly rubberband forwards) - ending a charge by running out of charge meter (you will suddenly rubberband backwards) - ending a charge by hitting an obstacle (walls, players, etc) - the charge regen itself (constant pred errors with cl_showerror 2 while your charge is regenerating)

(https://github.com/ValveSoftware/Source-1-Games/issues/6017)