[pkg/stanza] SeverityText is not properly preserved

[BinaryFissionGames]

Describe the bug
SeverityText is held on the stanza entry, but during conversion, is dropped for a SeverityText derived from the SeverityNumber.

Steps to reproduce
Using the following config:

Config

receivers:
  filelog:
    include:
      - local/test.log
    start_at: beginning
    operators:
      - type: regex_parser
        regex: '^(?P<severity>\w+) .*$'
        severity:
          parse_from: attributes.severity
          mapping:
            info: "INFO_SEVERITY"

exporters:
  logging:
    loglevel: debug

service:
  pipelines:
    logs:
      receivers: [filelog]
      exporters: [logging]
  telemetry:
    metrics:
      level: none

Sample Log

INFO_SEVERITY this is some info

What did you expect to see?
I expect SeverityText on the emitted log record to be "INFO_SEVERITY"

What did you see instead?
The SeverityText is "Info"

What version did you use?
Version: 73b3ae5

Additional context
The severity text is preserved on the stanza entry, but is not mapped to the OTel entry:

opentelemetry-collector-contrib/pkg/stanza/adapter/converter.go

Line 341 in 4ac2eb5

dest.SetSeverityText(sevTextMap[ent.Severity])