refactor(common.ts): moved size of empty array to constant file

src/constants/common.ts

+export const SIZE_OF_EMPTY_ARRAY = 0;

src/redux/chemicals/chemicals.selectors.ts

+import { SIZE_OF_EMPTY_ARRAY } from '@/constants/common';
 import { rootSelector } from '@/redux/root/root.selectors';
 import { createSelector } from '@reduxjs/toolkit';
 
-const SIZE_OF_EMPTY_ARRAY = 0;
-
 export const chemicalsSelector = createSelector(rootSelector, state => state.chemicals);
 
 export const loadingChemicalsStatusSelector = createSelector(

src/redux/drugs/drugs.selectors.ts

+import { SIZE_OF_EMPTY_ARRAY } from '@/constants/common';
 import { rootSelector } from '@/redux/root/root.selectors';
 import { createSelector } from '@reduxjs/toolkit';
 
-const SIZE_OF_EMPTY_ARRAY = 0;
-
 export const drugsSelector = createSelector(rootSelector, state => state.drugs);
 
 export const loadingDrugsStatusSelector = createSelector(drugsSelector, state => state.loading);

src/redux/mirnas/mirnas.selectors.ts

+import { SIZE_OF_EMPTY_ARRAY } from '@/constants/common';
 import { rootSelector } from '@/redux/root/root.selectors';
 import { createSelector } from '@reduxjs/toolkit';
 
-const SIZE_OF_EMPTY_ARRAY = 0;
-
 export const mirnasSelector = createSelector(rootSelector, state => state.mirnas);
 
 export const loadingMirnasStatusSelector = createSelector(mirnasSelector, state => state.loading);