SvxSearchDialog: Remove always false bMultiLineEdit.

Seems to be at least from 5c4b13d1bea4aedb72677f0317d5334638c03918.
'searchformat' and 'replaceformat' becomes then unused too.

Change-Id: Id5276e22478e5f863c12eadd7a7172d80ea685bb
MSG_SEARCH_FOO unused

Change-Id: I61ed39e3fc6ba1a6fe024693683f32a6a7ca88f1
GetSearchDialog() returns SvxSearchDialog; and use it in more places too.
fdo#74132: Do not interrupt search in Calc.

Extending f25cdaa78d5e7d200fbaf31cce9895bab7c5ee63
"fdo#74132: Do not interrupt search in Writer." for Calc.

Change-Id: I3a7e5070300993d2811a79f17cb1b2edb0355c44