fix(admin): Handle NaN in admin results

[evanh]

Python will encode NaN into JSON, even though it's not actually valid JSON.
This will cause the frontend to error out. Handle this case for the admin tool.

[codecov]

❌ 1 Tests Failed:

Tests completed	Failed	Passed	Skipped
554	1	553	1

View the top 1 failed tests by shortest run time

tests.admin.clickhouse.test_tracing test_scrub

Stack Traces | 0.001s run time

Traceback (most recent call last):
  File ".../admin/clickhouse/test_tracing.py", line 5, in test_scrub
    assert scrub_row((1, 2, 3, "release name")) == (1, 2, 3, "<scrubbed: str>")
  File ".../admin/clickhouse/tracing.py", line 62, in scrub_row
    if math.isnan(val):
       ^^^^^^^^^^^^^^^
TypeError: must be real number, not str

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