[hid_core, input_common] use std::numbers::pi{_v} instead of re-defining (#4160)

don't reinvent the wheel, simple as that.

Signed-off-by: lizzie <lizzie@eden-emu.dev>

Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/4160
Reviewed-by: MaranBr <maranbr@eden-emu.dev>
Reviewed-by: CamilleLaVey <camillelavey99@gmail.com>

src/common/math_util.h

@@ -1,4 +1,4 @@
-// SPDX-FileCopyrightText: Copyright 2025 Eden Emulator Project
+// SPDX-FileCopyrightText: Copyright 2026 Eden Emulator Project
 // SPDX-License-Identifier: GPL-3.0-or-later
 
 // SPDX-FileCopyrightText: 2013 Dolphin Emulator Project
@@ -13,8 +13,6 @@
 
 namespace Common {
 
-constexpr float PI = 3.1415926535f;
-
 template <class T>
 struct Rectangle {
     T left{};