Prioritize power symbols over hidden power pins on non-power symbols when determining net name

Description

Power symbol net name it's been overridden by pin component name (which has stacked/hidden pins defined as power input)

Steps to reproduce

1. Recording how to reproduced the bug on the attached prj is also available as attachment

KiCad Version

Application: KiCad

Version: 5.99.0-unknown-2e3860de6f~128~ubuntu20.04.1, release build

Libraries:
	wxWidgets 3.0.4
	libcurl/7.68.0 OpenSSL/1.1.1f zlib/1.2.11 brotli/1.0.7 libidn2/2.2.0 libpsl/0.21.0 (+libidn2/2.2.0) libssh/0.9.3/openssl/zlib nghttp2/1.40.0 librtmp/2.3

Platform: Linux 5.4.0-72-generic x86_64, 64 bit, Little endian, wxGTK, KDE, x11

Build Info:
	Date: May  6 2021 08:51:18
	wxWidgets: 3.0.4 (wchar_t,wx containers,compatible with 2.8) GTK+ 3.24
	Boost: 1.71.0
	OCC: 7.3.0
	Curl: 7.68.0
	ngspice: 31
	Compiler: GCC 9.3.0 with C++ ABI 1013

Build settings:
	KICAD_SCRIPTING=ON
	KICAD_SCRIPTING_MODULES=ON
	KICAD_SCRIPTING_PYTHON3=ON
	KICAD_SCRIPTING_WXPYTHON=ON
	KICAD_SCRIPTING_WXPYTHON_PHOENIX=ON
	KICAD_SCRIPTING_ACTION_MENU=ON
	KICAD_USE_OCC=ON
	KICAD_SPICE=ON

Test_v6.zip kicadv6_bug-2021-05-10_18.11.08_VO.mkv