Describe the solution you'd like

This issue reopens the discussion started on #34696, which had a PR (by me) #39948 that was merged into core and then reverted because it introduced side effects that were not discovered before the merge.

The issue

In some jurisdictions, for example, in Portugal, it is mandatory by law to show the start and end dates next to any sale price.
As another user mentioned, there are also marketing and advertising platforms that require the sale dates to be provided.

WooCommerce clears the sale start date at the time the sale is initiated by the cron job that runs wc_scheduled_sales, which makes it impossible to show it on the frontend with custom code, or integrate it into a product feed.

As mentioned in the original issue, there seems to be no rationale for this, except for the cleanliness of the database, which, to me, makes little sense when there are legal and marketing reasons to keep that date in the database at least until the end of the sale.

As mentioned before, my PR ended up having a side effect that I wasn't able to address, although I did investigate and found the problem.

At the time, I asked someone from core with more in-depth knowledge of the process to look into this issue and try to fix it without breaking anything. That original issue ended up closed by the fact that the PR was merged, and no one looked into this again.

Almost two weeks ago, I was part of the organizing team of a 100% ecommerce dedicated WordPress in Porto, Portugal, where attendees once again talked about this, and about the fact that some stores were already subject to fines by ASAE (commercial authority) because they didn't include the start and end date next to the sale price on their shops. This was also addressed in a compliance talk.

Currently, the solution adopted by store owners is to write the dates manually in the product description. There must be a better way...
This issue does not pertain to WooCommerce showing the dates on the frontend. It has the objective of ensuring the data exists when someone needs to use it, for legal or marketing reasons.

In short

Can someone look into this issue, my original PR, the comments on the original issue, and the PR, and find a solution to fix this?

Describe alternatives you've considered

No response

Additional context

No response