Crash in brave_ads::ConfirmationStateManager::GetUnblindedPaymentTokens

[aseren]

The corresponding Brave Browser issue: brave/brave-browser#31524.

Test plan is in brave/brave-core#19222.

Version 1.53.102

BraveCore`brave_ads::UnblindedTokensPermissionRule::ShouldAllow:
  0x10bcfab98 <+0>: sub  sp, sp, #0x30
  0x10bcfab9c <+4>: stp  x20, x19, [sp, #0x10]
  0x10bcfaba0 <+8>: stp  x29, x30, [sp, #0x20]
  0x10bcfaba4 <+12>: add  x29, sp, #0x20
  0x10bcfaba8 <+16>: mov  x19, x8
  0x10bcfabac <+20>: bl   0x6291c0         ; brave_ads::ShouldRewardUser at account_util.cc:20
  0x10bcfabb0 <+24>: cbz  w0, 0x65ebc0       ; <+40> at unblinded_tokens_permission_rule.cc
  0x10bcfabb4 <+28>: bl   0x6b7d20         ; brave_ads::privacy::UnblindedTokenCount at unblinded_token_util.cc:80
-> 0x10bcfabb8 <+32>: cmp  x0, #0x9
  0x10bcfabbc <+36>: b.ls  0x65ebcc         ; <+52> [inlined] base::unexpected<char const*>::unexpected<char const (&) [40], 0>(char const (&) [40]) at expected.h:180:9
  0x10bcfabc0 <+40>: mov  w8, #0x1
  0x10bcfabc4 <+44>: str  x8, [x19, #0x18]
  0x10bcfabc8 <+48>: b   0x65ebe4         ; <+76> at unblinded_tokens_permission_rule.cc:34:1
  0x10bcfabcc <+52>: adrp  x8, 6654
  0x10bcfabd0 <+56>: add  x8, x8, #0x9d0      ; "You do not have enough unblinded tokens"
  0x10bcfabd4 <+60>: str  x8, [sp, #0x8]
  0x10bcfabd8 <+64>: add  x1, sp, #0x8
  0x10bcfabdc <+68>: mov  x0, x19
  0x10bcfabe0 <+72>: bl   0x5818b8         ; absl::variant_internal::VariantStateBase<absl::monostate, std::Cr::basic_string<char, std::Cr::char_traits<char>, std::Cr::allocator<char> >, std::Cr::basic_string<char, std::Cr::char_traits<char>, std::Cr::allocator<char> > >::VariantStateBase<2ul, char const*> at variant.h:1039
  0x10bcfabe4 <+76>: ldp  x29, x30, [sp, #0x20]
  0x10bcfabe8 <+80>: ldp  x20, x19, [sp, #0x10]
  0x10bcfabec <+84>: add  sp, sp, #0x30
  0x10bcfabf0 <+88>: ret

[Uni-verse]

Verified on iPhone X running iOS 16.5.1 using version 1.56 (23.7.19.18)

Test Scenario:

1. Install 1.56.x Dev channel build
2. In the BraveCore switches, enable Log Verbosity level 6 (/brave/=6)
3. Relaunch browser
4. Enable Brave Rewards
5. Monitor logs to confirm unblindedpaymenttokens get refilled
6. Confirm ads are being shown

• Verified unblinded tokens are refilled intially.
• Verified ads are shown, both inline ads and ad notifications