Remove `update_database_metrics`

[tilacog]

After https://github.com/cowprotocol/infrastructure/pull/4611, we no longer need the update_database_metrics function:

services/crates/autopilot/src/database/mod.rs

Lines 79 to 97 in ff38a3e

	pub async fn update_database_metrics(&self) -> sqlx::Result<()> {
	let metrics = Metrics::get();
	let mut ex = self.pool.acquire().await?;
	// update table row metrics
	for &table in database::TABLES {
	let count = count_rows_in_table(&mut ex, table).await?;
	metrics.table_rows.with_label_values(&[table]).set(count);
	}
	// update table row metrics
	for &table in database::LARGE_TABLES {
	let count = estimate_rows_in_table(&mut ex, table).await?;
	metrics.table_rows.with_label_values(&[table]).set(count);
	}
	Ok(())
	}

[jmg-duarte]

I don't see how the infrastructure PR has the same side effect of helping the query estimator