[syslogexporter] set defaults for sending_queue and retry_on_failure and fix errors reported by golangci-lint

[kasia-kujawa]

Summary of changes:

• fix(syslogexporter): set default settings for sending_queue and retry_on_failure
  default setting are now set to defaults in exporterhelper,
  one expection - sending queue is enabled by default in syslog exporter

• chore(syslogexporter): fix errors reported by golangci-lint in opentelemetry-collector-contrib repository

List of reported errors:

/Users/kkujawa/git/opentelemetry-collector-contrib/.tools/golangci-lint run --allow-parallel-runners --build-tags integration
utils.go:38:5: increment-decrement: should replace errorsWithCounts[i].count += 1 with errorsWithCounts[i].count++ (revive)
                                errorsWithCounts[i].count += 1
                                ^
config.go:28:2: error-naming: error var unsupportedPort should have name of the form errFoo (revive)
        unsupportedPort     = errors.New("unsupported port: port is required, must be in the range 1-65535")
        ^
config.go:29:2: error-naming: error var invalidEndpoint should have name of the form errFoo (revive)
        invalidEndpoint     = errors.New("invalid endpoint: endpoint is required, must be a valid FQDN or IP address")
        ^
config.go:30:2: error-naming: error var unsupportedProtocol should have name of the form errFoo (revive)
        unsupportedProtocol = errors.New("unsupported protocol: protocol is required, only tcp/udp supported")
        ^
config.go:31:2: error-naming: error var unsupportedFormat should have name of the form errFoo (revive)
        unsupportedFormat   = errors.New("unsupported format: Only rfc5424 and rfc3164 supported")
        ^
syslog.go:41:7: var-naming: const msgId should be msgID (revive)
const msgId = "msg_id"
      ^
utils_test.go:83:22: unnecessary conversion (unconvert)
                        expected: []string([]string{"failed sending data: 502 Bad Gateway",
                                          ^
exporter.go:127:39: `(*syslogexporter).sendSyslogs` - `ctx` is unused (unparam)
func (se *syslogexporter) sendSyslogs(ctx context.Context, rl plog.ResourceLogs) ([]plog.LogRecord, error) {
                                      ^
utils.go:54:63: non-wrapping format verb for fmt.Errorf. Use `%w` to format errors (errorlint)
                        uniqueErrors = append(uniqueErrors, fmt.Errorf("%s (x%d)", errorWithCount.err, errorWithCount.count))
                                                                                   ^
exporter_test.go:177:42: type assertion on error will fail on wrapped errors. Use errors.As to check for specific errors (errorlint)
        consumerLogs := consumererror.Logs.Data(consumerErr.(consumererror.Logs))
                                                ^
factory.go:43:5: unusedwrite: unused write to field Enabled (govet)
        qs.Enabled = false
           ^
factory_test.go:35:5: unusedwrite: unused write to field Enabled (govet)
        qs.Enabled = false
           ^
make: *** [lint] Error 1