SDK, Dashboard: Fix error when airdropping decimal token amount in new token creation flow (#7866)

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## PR-Codex overview
This PR focuses on changing the data type of the `amount` property in the `DistributeContent` type and related usages from `bigint` to `string` to accommodate string representations of numbers.

### Detailed summary
- Changed `amount` type in `DistributeContent` from `bigint` to `string`.
- Updated `amount` assignment in `create-token-page-impl.tsx` to use `recipient.quantity` directly as a `string`.
- Modified the total amount calculation to sum `recipient.quantity` as `Number` instead of `BigInt`.

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<!-- This is an auto-generated comment: release notes by coderabbit.ai -->

## Summary by CodeRabbit

* **Bug Fixes**
  * Fixed inconsistencies in token airdrop amount handling, ensuring accurate totals and smoother approvals.
  * Resolved submission issues caused by mismatched numeric formats during distribution.

* **Refactor**
  * Standardized how token distribution amounts are represented to improve compatibility with forms and API requests.
  * Simplified airdrop calculations for better reliability and user experience.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Author: MananTank

apps/dashboard/src/app/(app)/team/[team_slug]/[project_slug]/(sidebar)/tokens/create/token/create-token-page-impl.tsx

@@ -179,7 +179,7 @@ export function CreateTokenAssetPage(props: {
       chain: contract.chain,
       client: props.client,
       contents: values.airdropAddresses.map((recipient) => ({
-        amount: BigInt(recipient.quantity),
+        amount: recipient.quantity,
         recipient: recipient.address,
       })),
       tokenAddress: contract.address,
@@ -200,8 +200,8 @@ export function CreateTokenAssetPage(props: {
     const contract = getDeployedContract({ chain: values.chain });
 
     const totalAmountToAirdrop = values.airdropAddresses.reduce(
-      (acc, recipient) => acc + BigInt(recipient.quantity),
-      0n,
+      (acc, recipient) => acc + Number(recipient.quantity),
+      0,
     );
 
     const entrypoint = await getDeployedEntrypointERC20({

packages/thirdweb/src/tokens/types.ts

@@ -22,7 +22,7 @@ export type PoolConfig = {
 };
 
 export type DistributeContent = {
-  amount: bigint;
+  amount: string;
   recipient: string;
 };