fix(tracefunnel): quote step names in slow and error trace queries (#12886)

#### Description

- `#12593` moved the n-step trace-funnel query builders onto
`clickhousesql.StringLiteral`, but the two-step `slow-traces` and
`error-traces` builders still interpolated `service_name`/`span_name`
into the SQL string literal raw.
- Route those four values through the same helper, so every funnel query
builder quotes step names consistently.

#### Additional Information

- No behaviour change for ordinary names; the
`slow-traces`/`error-traces` funnel queries now handle names containing
a quote the same way the rest of the module already does.

pkg/modules/tracefunnel/clickhouse_queries.go

@@ -495,8 +495,8 @@ WITH
     toDateTime64(%[3]d/1e9, 9) AS start_ts,
     toDateTime64(%[4]d/1e9, 9) AS end_ts,
 
-    ('%[5]s','%[6]s') AS step1,
-    ('%[7]s','%[8]s') AS step2
+    (%[5]s,%[6]s) AS step1,
+    (%[7]s,%[8]s) AS step2
 
 SELECT
     trace_id,
@@ -527,10 +527,10 @@ LIMIT 5;
 		containsErrorT2,
 		startTs,
 		endTs,
-		serviceNameT1,
-		spanNameT1,
-		serviceNameT2,
-		spanNameT2,
+		clickhousesql.StringLiteral(serviceNameT1),
+		clickhousesql.StringLiteral(spanNameT1),
+		clickhousesql.StringLiteral(serviceNameT2),
+		clickhousesql.StringLiteral(spanNameT2),
 		clauseStep1,
 		clauseStep2,
 		t1TimeExpr,
@@ -571,8 +571,8 @@ WITH
     toDateTime64(%[3]d/1e9, 9) AS start_ts,
     toDateTime64(%[4]d/1e9, 9) AS end_ts,
 
-    ('%[5]s','%[6]s') AS step1,
-    ('%[7]s','%[8]s') AS step2
+    (%[5]s,%[6]s) AS step1,
+    (%[7]s,%[8]s) AS step2
 
 SELECT
     trace_id,
@@ -607,10 +607,10 @@ LIMIT 5;
 		containsErrorT2,
 		startTs,
 		endTs,
-		serviceNameT1,
-		spanNameT1,
-		serviceNameT2,
-		spanNameT2,
+		clickhousesql.StringLiteral(serviceNameT1),
+		clickhousesql.StringLiteral(spanNameT1),
+		clickhousesql.StringLiteral(serviceNameT2),
+		clickhousesql.StringLiteral(spanNameT2),
 		clauseStep1,
 		clauseStep2,
 		t1TimeExpr,