fix(loki.source.file): Close file if we cannot find encoding [backport] (#5531)

## Backport of #5528

This PR backports #5528 to release/v1.13.

### Original PR Author
@kalleep

### Description
### Pull Request Details
Noticed that we do not close file if we cannot get encoding. Review all
other paths and we close file properly.

I really wish go had something like [errdefer like zig
does](https://ziglang.org/documentation/master/#errdefer).

### Issue(s) fixed by this Pull Request

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### Notes to the Reviewer

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### PR Checklist

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- [ ] Documentation added
- [ ] Tests updated
- [ ] Config converters updated


---
*This backport was created automatically.*

Co-authored-by: Karl Persson <23356117+kalleep@users.noreply.github.com>

Author: grafana-alloybot[bot]

internal/component/loki/source/file/internal/tail/file.go

@@ -28,6 +28,7 @@ func NewFile(logger log.Logger, cfg *Config) (*File, error) {
 
 	encoding, err := getEncoding(cfg.Encoding)
 	if err != nil {
+		f.Close()
 		return nil, err
 	}