docs: fix the 'list all items in a drive' sample (#1070)

[eduardarbona (earbona23)]

Fixes #1070 (and the earlier #365, which was closed without a fix).

The bug

Sample 3 in docs/drives_samples.md was:

items = await client.drives.by_drive_id('DRIVE_ID').items.get()   # GET /drives/{id}/items

GET /drives/{id}/items is not an enumerable collection in Microsoft Graph — it
addresses driveItems by id and only answers $filter queries — so following the sample
returns exactly the error nine people reacted to:

The 'filter' query option must be provided.

The SDK and Graph are both behaving correctly; the sample documented a call that cannot
work. #365 reported this and was closed with no fix while the broken sample stayed in place.

The fix

Sample 3 now does what its title says — list all the items — by walking root with
delta and paging through odata_next_link:

page = await client.drives.by_drive_id('DRIVE_ID').items.by_drive_item_id('root').delta.get()
while page:
    if page.value:
        for item in page.value:
            print(item.id, item.name, item.size, item.folder, item.file)
    if not page.odata_next_link:
        break
    page = await client.drives.by_drive_id('DRIVE_ID').items.by_drive_item_id('root').delta.with_url(page.odata_next_link).get()

This also removes an overlap: as written, sample 3 duplicated sample 6 (which lists only the
top level via root/children). Now 3 is the recursive listing and 6 is the top-level one,
with a cross-reference between them so the distinction is explicit.

Verified against the generated SDK in this repo

• items.by_drive_item_id('root').delta — msgraph/generated/drives/item/items/item/delta/delta_request_builder.py
• .with_url() for paging — same file, line 65
• odata_next_link and value on the response — inherited from BaseDeltaFunctionResponse (msgraph/generated/models/base_delta_function_response.py:18)
• the snippet parses as valid Python

Docs-only, one file. I did not run it against a live drive (no tenant), so if a maintainer
runs it and sees anything off with the paging, tell me and I will adjust — but every symbol
it uses is confirmed present in the generated client.

[eduardarbona (earbona23)]

@microsoft-github-policy-service agree