Fixes issue with ads per day incorrectly limited to ads per hour - 1.18.x

[tmancey]

Uplift of #7454
Resolves brave/brave-browser#13215

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[kjozwiak]

test-browser failed on macOS due to several reward failures as per https://ci.brave.com/job/pr-brave-browser-issues-13215-1.18.x-macos/2/execution/node/202/log/. However, these are known intermittent issues and have the following associated GH issues:

• RewardsBrowserTest.ResetRewardsWithBAT --> Rewards browser test intermittent failure: RewardsContributionBrowserTest.TipUnverifiedPublisher and RewardsBrowserTest.ResetRewardsWithBAT brave-browser#12607
• RewardsBrowserTest.UpholdLimitNoBAT --> "RewardsBrowserTest.UpholdLimitNoBAT" failing CI intermittently brave-browser#12704

11:33:25  2 tests failed:
11:33:25      RewardsBrowserTest.ResetRewardsWithBAT (../../brave/components/brave_rewards/browser/test/rewards_browsertest.cc:374)
11:33:25      RewardsBrowserTest.UpholdLimitNoBAT (../../brave/components/brave_rewards/browser/test/rewards_browsertest.cc:397)

[kjozwiak]

Uplift into 1.18.x approved after deliberating with @brave/uplift-approvers. QA has verified the PR on Nightly as per #7454 (comment).