fix(loki.source.file): Close file if we cannot find encoding (#5528)

### 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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### PR Checklist

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

(cherry picked from commit 56bcb26)

Author: kalleep

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
 	}