review links in charter page; remove obsolete CG drafts

[VladimirAlexiev]

https://www.w3.org/2024/12/data-shapes.html

There is an evolving SHACL 1.2 Core draft.
There is an evolving SHACL 1.2 SPARQL Extensions draft.

But these are Draft Community Group Reports of an older date (27 January 2025)
and their "Latest editor's draft" links (eg https://w3c.github.io/shacl/shacl12-sparql/) are broken.

Please

• replace the links in charter with https://w3c.github.io/data-shapes/shacl12-core/ , https://w3c.github.io/data-shapes/shacl12-sparql/
• remove the above CG reports, or clearly mark them as obsolete, and fix the broken "Latest editor's draft" links

[caribouW3]

We generally don't update the charter with links of published documents during the WG life, those links specifically refer to starting points (the CG reports) for the WG work (the ED).
We could fix the links in the CG reports but that would probably change the date when regenerating the documents, I'm not sure it's desirable.