SSDM-13256: Fixing the issue with "$$" being exported. Fixing failing tests.

.../xls/export/helper/AbstractXLSEntityTypeExportHelper.java

...penbis/generic/server/xls/export/DataSetExpectations.java

...is/generic/server/xls/export/DataSetTypeExpectations.java

...generic/server/xls/export/ExperimentTypeExpectations.java

...bis/generic/server/xls/export/SampleTypeExpectations.java

.../export/SampleTypeWithBareSamplePropertyExpectations.java

...rt/SampleTypeWithChainedSamplePropertiesExpectations.java

...ort/SampleTypeWithCyclicSamplePropertiesExpectations.java

.../xls/export/SampleTypeWithSamplePropertyExpectations.java

.../export/SampleTypeWithVocabularyPropertyExpectations.java

...rver/xls/export/resources/export-data-set-plain-text.xlsx

...erver/xls/export/resources/export-data-set-rich-text.xlsx

...xport/resources/export-sample-compatible-with-import.xlsx

...export-sample-filtered-fields-compatible-with-import.xlsx