…#51592)

* fix: ship IDS_WEBAUTHN_TOUCH_ID_PROMPT_REASON and allow overriding it

Pack device/fido strings into the locale .pak files so
IDS_WEBAUTHN_TOUCH_ID_PROMPT_REASON ("verify your identity on $1") is
present at runtime. Previously the resource was never repacked, so the
macOS Touch ID prompt for WebAuthn requests crashed when looking up the
missing IDS string.

Also lets apps override the prompt text via
configureWebAuthn({ touchID: { promptReason } }) using
ResourceBundle::OverrideLocaleStringResource. An optional $1 placeholder
is replaced with the relying party ID; without it the string is used
verbatim.

* build: make //device/fido/strings an unconditional electron_lib dep

gn check does not evaluate preprocessor conditionals, so it flags the
mac-only #include of fido_strings.h on Linux/Windows even though the
include is behind BUILDFLAG(IS_MAC). Depend on //device/fido/strings on
all platforms to satisfy the header check.