Allow input and display of floats for Number fields (#7340)

### Description

- We added a decimal field for a Number Field type in the settings
- We updated the Number Field type create a form with decimals input
- We are not implementing the dropdown present on the Figma because it
seems not related

### Demo


<https://www.loom.com/share/18a8d4b712a14f6d8b66806764f8467f?sid=3fc79b46-ae32-46e3-8635-d0eee02e53b2>

Fixes #6987

---------

Co-authored-by: gitstart-twenty <gitstart-twenty@users.noreply.github.com>
Co-authored-by: Marie Stoppa <marie.stoppa@essec.edu>

packages/twenty-front/src/utils/cast-as-number-or-null.ts

@@ -0,0 +1,75 @@
+import { isNull, isNumber, isString } from '@sniptt/guards';
+
+import { logError } from './logError';
+
+const DEBUG_MODE = false;
+
+export const canBeCastAsNumberOrNull = (
+  probableNumberOrNull: string | undefined | number | null,
+): probableNumberOrNull is number | null => {
+  if (probableNumberOrNull === undefined) {
+    if (DEBUG_MODE) logError('probableNumberOrNull === undefined');
+
+    return false;
+  }
+
+  if (isNumber(probableNumberOrNull)) {
+    if (DEBUG_MODE) logError('typeof probableNumberOrNull === "number"');
+
+    return true;
+  }
+
+  if (isNull(probableNumberOrNull)) {
+    if (DEBUG_MODE) logError('probableNumberOrNull === null');
+
+    return true;
+  }
+
+  if (probableNumberOrNull === '') {
+    if (DEBUG_MODE) logError('probableNumberOrNull === ""');
+
+    return true;
+  }
+
+  if (isString(probableNumberOrNull)) {
+    const stringAsNumber = +probableNumberOrNull;
+
+    if (isNaN(stringAsNumber)) {
+      if (DEBUG_MODE) logError('isNaN(stringAsNumber)');
+
+      return false;
+    }
+    if (isNumber(stringAsNumber)) {
+      if (DEBUG_MODE) logError('isNumber(stringAsNumber)');
+
+      return true;
+    }
+  }
+
+  return false;
+};
+
+export const castAsNumberOrNull = (
+  probableNumberOrNull: string | undefined | number | null,
+): number | null => {
+  if (canBeCastAsNumberOrNull(probableNumberOrNull) === false) {
+    throw new Error('Cannot cast to number or null');
+  }
+
+  if (isNull(probableNumberOrNull)) {
+    return null;
+  }
+
+  if (isString(probableNumberOrNull)) {
+    if (probableNumberOrNull === '') {
+      return null;
+    }
+    return +probableNumberOrNull;
+  }
+
+  if (isNumber(probableNumberOrNull)) {
+    return probableNumberOrNull;
+  }
+
+  return null;
+};