bugfix:fix the problem in the findTargetClass method

[ls9527]

Ⅰ. Describe what this PR did

修复获取代理对象类型时, 由于未判断静态类型引起的spring-security框架结合是无法启动的问题

Ⅱ. Does this pull request fix one issue?

fixes #3709

Ⅲ. Why don't you add test cases (unit test/integration test)?

Ⅳ. Describe how to verify it

在官方提供的例子中
seata-samples->sprngboot-mybatis-sbm-sorage-service项目中
加入maven引用

        <dependency>
            <groupId>org.springframework.security.oauth</groupId>
            <artifactId>spring-security-oauth2</artifactId>
            <version>2.2.0.RELEASE</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-security</artifactId>
            <version>2.2.0.RELEASE</version>
        </dependency>

在启动类的Application类上加入注解 @EnableOAuth2Client

在1.4.2版本下就可以重现#issue 3709的问题。

Ⅴ. Special notes for reviews

[codecov-commenter]

Codecov Report

Merging #3716 (83317ea) into develop (b7b674e) will decrease coverage by 0.00%.
The diff coverage is 0.00%.

❗ Current head 83317ea differs from pull request most recent head 6200cf3. Consider uploading reports for the commit 6200cf3 to get more accurate results

@@              Coverage Diff              @@
##             develop    #3716      +/-   ##
=============================================
- Coverage      51.88%   51.87%   -0.01%     
- Complexity      3533     3534       +1     
=============================================
  Files            639      639              
  Lines          21414    21416       +2     
  Branches        2665     2666       +1     
=============================================
- Hits           11111    11110       -1     
- Misses          9193     9197       +4     
+ Partials        1110     1109       -1     

Impacted Files	Coverage Δ	Complexity Δ
...in/java/io/seata/spring/util/SpringProxyUtils.java	3.70% <0.00%> (-0.15%)	3.00 <0.00> (ø)
...n/src/main/java/io/seata/common/util/IdWorker.java	77.08% <0.00%> (-6.25%)	11.00% <0.00%> (-1.00%)
...in/java/io/seata/server/session/GlobalSession.java	83.47% <0.00%> (+0.43%)	76.00% <0.00%> (+1.00%)
...o/seata/server/coordinator/DefaultCoordinator.java	52.58% <0.00%> (+0.46%)	28.00% <0.00%> (+1.00%)

[funky-eyes]

LGTM 请在changes文件夹中登记此pr及作者信息到两个1.5.0md中

[xingfudeshi]

LGTM.