incorrect interpolating query with variable inside the reg exp

[frli4797]

Describe the bug

When using a query like _time:16h {host=~"(?i)$host",job="rsyslog",level=~"(error|warning|critical)"}
an error message is generated and nothing is returned by the query.

error from datasource: cannot parse query [_time:16h {host=~"(?i)"hostname"",job="rsyslog",level=~"(error|warning|critical)"} | sort by (_time) desc]: unexpected token "hostname" in _stream filter after "host=~\"(?i)\""; want 'or', 'and', '}' or ','; context: [_time:16h {host=~"(?i)"hostname]

Running the query in vm-ui works fine, given that the variable is replaced with a valid hostname.

To Reproduce

Create a dashboard widget for a query like _time:16h {host=~"(?i)$host",job="rsyslog",level=~"(error|warning|critical)"}

Error is thrown

Versions of VictoriaLogs datasource and VictoriaLogs backend

Version: victoria-logs-20251114-183126-tags-v1.38.0-0-g83b6b92169
Plugin version: 0.21.4
Grafana: v12.2.1

Link to dashboard in Victoria Metrics

No response

Please provide dashboard JSON if it is possible

{
  "id": 157,
  "type": "logs",
  "title": "Syslog errors",
  "gridPos": {
    "x": 0,
    "y": 5,
    "h": 5,
    "w": 21
  },
  "fieldConfig": {
    "defaults": {},
    "overrides": []
  },
  "pluginVersion": "12.2.1",
  "targets": [
    {
      "datasource": {
        "type": "victoriametrics-logs-datasource",
        "uid": "ce80jyaoi1tz4b"
      },
      "editorMode": "code",
      "expr": "_time:16h {host=~\"(?i)$host\",job=\"rsyslog\",level=~\"(error|warning|critical)\"} ",
      "hide": false,
      "queryType": "instant",
      "refId": "A"
    }
  ],
  "datasource": {
    "type": "victoriametrics-logs-datasource",
    "uid": "ce80jyaoi1tz4b"
  },
  "interval": "1m",
  "options": {
    "showTime": true,
    "showLabels": false,
    "showCommonLabels": false,
    "wrapLogMessage": true,
    "prettifyLogMessage": false,
    "enableLogDetails": true,
    "enableInfiniteScrolling": false,
    "dedupStrategy": "none",
    "sortOrder": "Descending"
  },
  "timeFrom": "16h",
  "hideTimeOverride": false,
  "links": [
    {
      "title": "Details",
      "url": "http://metrics.domain.com/d/ddqxdmho6msjke/log-details?orgId=1&var-host=$host&var-job=rsyslog&var-level=critical&var-level=error&var-level=warning"
    }
  ]
}

Additional information

No response

[frli4797]

Worked previously on plugin version: 0.21.0