improve(bq_driver): SQLTables perf improvement

[Anshu6250]

perf result- link

Added google-cloud-cpp logs and can be verified with regex search "page_token: "[^"]" in file without max results there are 34 extra responses or can also search "next_page_token" which proves the hypothesis that is increasing the latency.
test_output_withoit_max_rsult.log
test_output_without_max_result.log

LiteralFromOdbcPattern method improves :- WildcardTableSearch majorly
With SQL_ATTR_METADATA_ID = SQL_FALSE, ODBC defines the catalog, schema and
table arguments as search patterns, and SQLTables treated all three that way
unconditionally. For a call that names an exact project and dataset, that meant
two wasted round trips before the useful one:

projects.list -> enumerate every visible project, regex-match to find the one named
datasets.list -> enumerate every dataset in it, regex-match to find the one named
tables.list -> the call we actually wanted

projects.list is the worst of the two: the API has no server-side name filter,
so it always returns everything just to select a name the caller already gave us.

LiteralFromOdbcPattern() checks whether a filter contains any unescaped % or
_. If it doesn't, the pattern can only ever match itself, so enumerate-then-match
is equivalent to using the name directly — the driver now does that and skips the
listing. This generalises the existing SQL_ATTR_METADATA_ID = SQL_TRUE fast path
to literal patterns.

No API call changed. No new endpoint, no changed request shape or parameters;
the surviving tables.list is identical, and the table-name filter is still matched
client-side as before. Two calls are simply no longer made. Escaped wildcards
(\_, \%) are unescaped and still treated as literals, so pattern semantics are
preserved.

EscapeOdbcPattern method improves :- FilterTablesOnDefaultDataset
When the application passes schema = NULL and the DSN sets
FilterTablesOnDefaultDataset=1, SQLTables substituted the configured dataset
name straight into dataset_filter — a variable everything downstream interprets
as an ODBC LIKE pattern. Since _ is a single-character wildcard, a configured
ODBC_TEST_DATASET compiles to ODBC.TEST.DATASET and also matches
ODBCxTESTyDATASET, so users could be shown tables from datasets they never
configured. BigQuery dataset names use _ as the conventional separator, so most
DSNs using this option are exposed.

EscapeOdbcPattern() escapes %, _ and \ at the substitution site so the name
matches only itself. It also lets the existing literal fast path skip
datasets.list for that call.

No API call changed — no new endpoint, no changed request shape; only how the
schema argument is interpreted before the existing calls are made.