[forms] Fix HTableFormRenderer _render_fields method behavior when display_label is False.
Indeed, now the extra <tr><th>...</th></tr> are not inserted anymore unless
display_label is True.
Closes #3811325.
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.*/data.*/database/.*
.*/data/ldapdb/.*
.*/data/uicache/
.*/data/cubes/.*/i18n/.*\.po
^doc/html/
^doc/doctrees/
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^doc/_build
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