Refactor collection.Base#construct to prevent race conditions during instantiation.

Is your feature request related to a problem? Please describe. Yes. During the instantiation of a Neo.collection.Base subclass (or a class that uses it, like Neo.data.Store), config setters can be triggered by the super.construct() call before the collection's internal properties are fully initialized.

A concrete example is in examples/grid/bigData/MainStore.mjs. The afterSetAmountRows method can be called during the store's construction. This method calls me.add(), which in turn calls the collection's splice() method.

The splice() method contains the logic if (me[updatingIndex] === 0). Before the construct method is refactored, the symbol properties like updatingIndex are defined after super.construct(). This means that when splice() is called during instantiation, me[updatingIndex] is undefined, causing the check to fail and preventing the mutate event from firing correctly.

Describe the solution you'd like The construct method of Neo.collection.Base should be refactored to initialize its internal symbol-based properties before calling super.construct(config).

The implementation should be changed from:

// Old implementation
construct(config) {
    super.construct(config);

    let me           = this,
        symbolConfig = {enumerable: false, writable: true};

    me.items = me.items || [];

    Object.defineProperties(me, {
        [countMutations]  : {...symbolConfig, value: false},
        [isFiltered]      : {...symbolConfig, value: false},
        [isSorted]        : {...symbolConfig, value: false},
        [silentUpdateMode]: {...symbolConfig, value: false},
        [toAddArray]      : {...symbolConfig, value: []},
        [toRemoveArray]   : {...symbolConfig, value: []},
        [updatingIndex]   : {...symbolConfig, value: 0}
    });

    if (me.autoSort && me._sorters.length > 0) {
        me.doSort()
    }
}

To:

// New implementation
construct(config) {
    let me           = this,
        symbolConfig = {enumerable: false, writable: true};

    Object.defineProperties(me, {
        [countMutations]  : {...symbolConfig, value: false},
        [isFiltered]      : {...symbolConfig, value: false},
        [isSorted]        : {...symbolConfig, value: false},
        [silentUpdateMode]: {...symbolConfig, value: false},
        [toAddArray]      : {...symbolConfig, value: []},
        [toRemoveArray]   : {...symbolConfig, value: []},
        [updatingIndex]   : {...symbolConfig, value: 0}
    });

    super.construct(config);

    me.items = me.items || [];

    if (me.autoSort && me._sorters.length > 0) {
        me.doSort()
    }
}

This ensures that properties like updatingIndex have their default value (0) set before any config setters are invoked, fixing the race condition.

Describe alternatives you've considered An alternative would be to add checks for undefined in all methods that use these symbol properties (e.g., if (me[updatingIndex] === 0 || me[updatingIndex] === undefined)). However, this is verbose, less clean, and only patches the symptoms. The proposed solution addresses the root cause of the initialization order problem.

Additional context This change makes the Collection class more robust and prevents subtle bugs in components that rely on it, especially when they perform data manipulations within their config setters.