Remove QT_NO_CAST_FROM_ASCII from QT_ENABLE_STRICT_MODE_UP_TO

QT_NO_CAST_FROM_ASCII is a policy setting, not a strictness
setting. The other components of QT_ENABLE_STRICT_MODE_UP_TO all deal
with clearly undesirable APIs, which QString(const char*) cannot be
said to be.

Keeping it in QT_ENABLE_STRICT_MODE_UP_TO would seriously impede the
use of strict mode in Qt itself (cf. QTBUG-132327).

Amends 3a6c8e02b6d1b0574da52b0087092d0c74aa92c1.

[ChangeLog][QtCore][QT_ENABLE_STRICT_MODE_UP_TO] No longer includes
QT_NO_CAST_FROM_ASCII. If you wish to continue using
QT_NO_CAST_FROM_ASCII, you need to define it in addition to
QT_ENABLE_STRICT_MODE_UP_TO. The reason for this change is that, while
everything else in strict mode should eventually become the default,
we're not proposing to remove the ability to construct a QString from
a const char*. QT_NO_CAST_FROM_BYTEARRAY and QT_NO_CAST_TO_ASCII
remain enabled in strict mode, though.

Task-number: QTBUG-132327
Pick-to: 6.8
Change-Id: I36b850833b1de79a47de975ca28d3591a0a0e089
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Ahmad Samir <a.samirh78@gmail.com>
(cherry picked from commit f9163ae7a8167daded0798654d99a2e3a5aaa2b5)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

src/corelib/global/qglobal.cpp

@@ -351,7 +351,6 @@ bool QInternal::activateCallbacks(Callback cb, void **parameters)
     \table
     \header \li Version \li Disabled APIs
     \row \li 6.0.0 \li \l{foreach-keyword}{foreach} (see \l{QT_NO_FOREACH})
-    \row \li 6.0.0 \li QString constructors from \c{const char *} (see \l{QT_NO_CAST_FROM_ASCII})
     \row \li 6.0.0 \li QString conversions towards \c{const char *} / QByteArray (see \l{QT_NO_CAST_TO_ASCII})
     \row \li 6.0.0 \li QByteArray implicit conversions towards \c{const char *} (see \l{QT_NO_CAST_FROM_BYTEARRAY})
     \row \li 6.0.0 \li QUrl implicit conversions from QString (see \l{QT_NO_URL_CAST_FROM_STRING})

src/corelib/global/qtconfigmacros.h

@@ -185,9 +185,6 @@ namespace QT_NAMESPACE {}
 # ifndef QT_NO_FOREACH
 #  define QT_NO_FOREACH
 # endif
-# ifndef QT_NO_CAST_FROM_ASCII
-#  define QT_NO_CAST_FROM_ASCII
-#endif
 # ifndef QT_NO_CAST_TO_ASCII
 #  define QT_NO_CAST_TO_ASCII
 # endif