fdo#72390: Let's not skip auto styles from unmodified sheets.

We do re-use sheet XML stream for unmodified sheets on re-save, which
is okay.  But skipping auto style population from unmodified sheets
is not okay because autostyles are shared across all sheets and written
outside the sheet XML streams. Skipping styles from unmodified sheets
could potentially fail to export used styles, not to mention could
cause a crash as reported in the bug.

Change-Id: I73e439f7354e341c2c07e28ecca5452193985860
(cherry picked from commit 5000e64ecc55efd47d92714cf6db375ff37aac4b)
(cherry picked from commit 47e540d8323e8ea2db5e7aae455503b32f306ca3)
fdo#72691: Allow overwriting of string value with numeric one.

This can legitimately happen when you have a matrix with a reference to
another cell inside, and the referenced cell originally contained a
string value then later overwritten by a numeric value.

Example.  Put a "Text" in A1, and in B1 put a 1x1 matrix {=A1}.  It
displays "Text" in B1.  Then put 11 in A1.  Prior to this change, B1
would become blank.  With this change, B1 will display 11.

Change-Id: I3feba3a8658e1a5ebf6f9e5ac34de2d579464ddb
(cherry picked from commit 9bf907a8278cecd816368db7b8c4ab745a914a59)
fdo#72491: Always set input as text when that's requested.

Even when the text begins with '='.

(cherry picked from commit ca50752c34de4477c696471b707e1b8136e27661)

Conflicts:
	sc/source/core/data/column3.cxx

Change-Id: I6e0a995f3042240b9f78068b5d0b9b758eb253ed