Fix missing freq param in cache update writer locks

[Ayush10]

Summary

• Pass freq to C.dpm.get_data_uri() in DiskExpressionCache.update() (line 594) and DiskDatasetCache.update() (line 961)
• Without freq, get_data_uri() falls back to DEFAULT_FREQ, which raises KeyError when only non-default frequencies are configured

Root Cause

Both update() methods receive a freq parameter but the writer lock calls C.dpm.get_data_uri() without forwarding it. This is inconsistent with all other call sites in the same file which correctly pass freq.

Test plan

• Verified all other get_data_uri call sites in cache.py pass freq (lines 324, 549, 727, 737, 778, 783, 1155)
• The two fixed lines are the only ones that were missing the parameter

Fixes #2012