Adds pending deprecations for Mount.from_* methods

[freider]

Will nudge users toward new replacements ahead of real deprecation with client 1.0

Describe your changes

• Provide Linear issue reference (e.g. MOD-1234) if available.

Backward/forward compatibility checks

---

Check these boxes or delete any item (or this section) if not relevant for this PR.

• Client+Server: this change is compatible with old servers
• Client forward compatibility: this change ensures client can accept data intended for later versions of itself

Note on protobuf: protobuf message changes in one place may have impact to
multiple entities (client, server, worker, database). See points above.

---

Changelog

[mwaskom]

Does making these pending=True have any practical implications for users? They seem equally visible.

[freider]

@prbot approve

[modal-pr-review-automation]

Approved 👍. @mwaskom will follow-up review this.

[kramstrom]

lgtm

[kramstrom]

Does making these pending=True have any practical implications for users? They seem equally visible.

It's only to not have them raised as errors in the tests right? Until we remove them and don't need the tests anymore