Upgrade blevesearch to v0.8.1 (#9177)

For #1441

https://github.com/blevesearch/bleve/commit/a91b427b59b893f112021841ba7370d285f8426f

vendor/github.com/blevesearch/bleve/document/field_text.go

@@ -86,6 +86,10 @@ func (t *TextField) Analyze() (int, analysis.TokenFrequencies) {
 	return fieldLength, tokenFreqs
 }
 
+func (t *TextField) Analyzer() *analysis.Analyzer {
+	return t.analyzer
+}
+
 func (t *TextField) Value() []byte {
 	return t.value
 }