fix(sql): fix alter table dedup enable syntax

[ideoma]

Both syntax variants are made valid

ALTER table abc DEDUP ENABLE UPSERT KEYS(a, b);

ALTER table abc DEDUP UPSERT KEYS(a, b);

Also fixed a bug where table was not shows as dedup enabled in tables() query when the timestamp index is 0.

[ideoma]

[PR Coverage check]

😍 pass : 17 / 17 (100.00%)

file detail

	path	covered line	new line	coverage
🔵	io/questdb/griffin/engine/functions/catalogue/TableListFunctionFactory.java	2	2	100.00%
🔵	io/questdb/cairo/DedupColumnCommitAddresses.java	3	3	100.00%
🔵	io/questdb/griffin/SqlCompilerImpl.java	2	2	100.00%
🔵	io/questdb/cairo/TableWriter.java	1	1	100.00%
🔵	io/questdb/griffin/SqlKeywords.java	9	9	100.00%